FIELD OF THE INVENTION

This invention relates to technical fields relating to actions on pi tuitary adenylate cyclase activating polypeptide (hereinafter referred to as "PACAP") receptors. More speci ficall y, the invention relates to use of peptides havi ng a specifi c affi nity to PACAP subtype 1 among subtypes of PACAP receptors .

BACKGROUND OF THE INVENTION

PACAP was i solated from the hypothalami of sheep as a peptide activating adenylate cyclase (see,

Biochem. Biophys. Res. Commun. , 567-574 (1989); Arimura, A, et al . , Regul . Peptides, 3_7, 287-303 (1992)) . The amino acid sequence of PACAP is identified as fol lows ( this i s hereinafter referred to as "PACAP 38") .

His Ser Asp Gly lie Phe Thr Asp Ser Tyr Ser Arg Tyr Arg Lys Gin

1 5 10 15

Met Ala Val Lys Lys Tyr Leu Ala Ala Val Leu Gly Lys Arg Tyr Lys 20 25 30 Gin Arg Val Lys Asn Lys-Nrl, 35

(SEQ ID NO: 4-NH ₂ ) Thereafter, the existence of PACAP 27 consist¬ i ng of the following shorter amino acid sequence at the N-termi nal si de were revealed:

His Ser Asp Gly lie Phe Thr Asp Ser Tyr Ser Arg Tyr Arg Lys Gin

1 5 10 15

Met Ala Val Lys Lys Tyr Leu Ala Ala Val Leu-NhL 20 25

(SEQ ID NO: 5-NH ₂ )

These PACAPs are considered to be members belonging to the secretin / glucagon / VIP family be¬ cause in comparison of amino acid sequence, homology of about 68 % is observed between these PACAPs and the amino acid sequence composed of 28 amino acid residues at the N-terminal side of VIP.

Since PACAP exhibits homology to VIP as men¬ tioned above, it was suggested that i t signaled through receptors analogous to VIP receptors. It is now known that at least three subtypes of PACAP receptors exist.

PACAP exhibits affi nity but VIP does not exhibit affini¬ ty to PACAP type 1 receptors, while both PACAP and VIP exhibit affinity to PACAP type 2 and PACAP type 3 recep¬ tors. PACAP type 2 receptors and PACAP type 3 receptors are also called VIP type 1 receptors and VIP type 2 receptors, respectively.

PACAP is widely distributed i n the body, for example, central nervous systems, testes, ovaries, adrenals, lungs, digestive tracts, pancreas, etc. , and i ts actions i s considered to range widely. As to the PACAP receptors, it is recognized that the type 1 is expressed at a high level in brains, but at a low level at adrenals and scarcely at other pri ncipal tissues, whereas the type 2 is recognized to be expressed in lungs, brains , smal l intestines, livers, etc. and the type 3 is recognized to be expressed in lungs, stomachs, small intesti nes, pancreas, etc. As is seen from the above, it is known that some extent of specificity exists in the tissue distribution of the PACAP recep- tors.

Agonists or antagonists having specific affin-^ i ty only to the type 1 PACAP receptor have not yet been disclosed in technical li teratures. Therefore, for determi ning, at the present point of time, whether or not targeted receptors among subtypes of PACAP receptors are type 1 , a bindi ng test wherein at least PACAP 38 or

PACAP 27, and VIP are used in combination as ligands, etc. must be used.

Therefore, provision of compounds exhibiting specifi c affi nity (or binding) to PACAP type 1 receptors will be desired even for merely exami ning functions of PACAP receptors.

On the other hand , part of the present inven¬ tors revealed that maxadi lan derived from the sal ivary gland of Lutzomyia longipalpis, and i ts mutants, when i nfected into epidermis of animals, cause erythema with¬ out itch and pain, and are extremely interesting peptides (see , for example, WO 91/00293; E.A. Lerner et al . , J. Bio. Chem. 267, 1062-1066 (1992)) . Further, they al so revealed that a pepti de (hereinaf ter referred to as "MAX") represented by the following amino acid sequence, among the mutants, exhibits a stronger erythema-forming action than natural maxadi lan (see, for example, U.S. Patent No. 5,480,864).

Gly Ser lie Leu Cys Asp Ala Thr Cys Gin Phe Arg Lys Ala He Asp 16 1 5 10 15

Asp Cys Gin Lys Gin Ala His His Ser Asn Val Leu Gin Thr Ser Val 32

20 25 30

Gin Thr Thr Ala Thr Phe Thr Ser Met Asp Thr Ser Gin Leu Pro Gly 48 35 40 45

Asn Ser Val Phe Lys Glu Cys Met Lys Gin Lys Lys Lys Glu Phe Lys 64

50 55 60

Ala Gly Lys 67

65 (SEQ ID NO: 1)

They still further revealed that other various mutants of maxadilan also exhibit maxadi 1 an-1 i ke biolog¬ i cal activities, and part of them have agonizing binding ability to the surfaces of the cell membranes of tis¬ sues, particularly tissues derived from brains of mam-

mals, and the other part have antagonizing binding ability thereto (see, U.S. Serial No. 08/540,033) .

SUMMARY OF THE INVENTION The present inventors examined affinity and action of mutants i ncludi ng MAX to or on various animal tissue preparations, and receptors known per se . As a result, they- found, surprisingly, that although there i s almost no homology between PACAP and MAX, as understood from the above amino acid sequences, MAX, and later- described NSP (SEQ ID NO: 2) and M65 (SEQ ID NO: 3) and their C-termi nus amidized peptides (these referred to as a peptide represented by MAX-NH _? or SEQ ID NO: 1-NH _{2 >} a peptide represented by NSP-NH. or SEQ ID NO: 2-NH _? , and a peptide represented by M65-NH ₂ or SEQ ID NO: 3-NH _j , respectively) exhibit specific sffini ty (or binding) to subtype receptors of type 1 among the PACAP type 1 , 2 and 3 r ecepto rs .

Thus, according to the invention is provided a test reagent for determining the subtype of PACAP recep¬ tors predicted to exist i n a tissue or cells derived f rom a mammal , the test reagent containing at least one peptide selected from the group consisting of peptides represented by SEQ ID NO: 1 , SEQ ID NO: 1-NH _{2 >} SEQ ID NO: 2, SEQ ID NO: 2-NH _? , SEQ ID NO: 3 and SEQ ID NO: 3-NH ₂ , and the subtype to be distinguished being PACAP t ype 1. The invention of this embodiment can conve¬ niently be utilized , for example, mai nly for classifi¬ cation of receptors of various animal cells , researches for elucidating functions of the receptors, etc.

As the invention of another, the second em- bodiment is provided a method for determining the sub¬ type of PACAP receptors predicted to exist in a tissue

or cells derived from a mammal, the method comprising steps of

(A) contacting the tissue or cells with at least one peptide selected from the group consisting of peptides represented by SEQ ID NO: 1, SEQ ID NO: 1-NH ₂ , SEQ ID NO: 2, SEQ ID NO: 2-NH ₂ , SEQ ID NO: 3 and SEQ ID NO: 3-NH ₂ ,

(B) assaying the affinity of the peptide to the tissue or cells, and (C) determining whether the subtype is PACAP type 1 or not , by assessing the speci ficity of the affinity.

As the invention of another, the third embodi¬ ment is provided a method for assessing the functions of PACAP type 1 receptor-expressing cells in a tissue derived from a mammal , the method comprising steps of

(a) contacting a tissue or cells predicted to contain the expressing cells with at least one peptide selected from the group consisting of peptides repre¬ sented by SEQ ID NO: 1. SEQ ID NO: 1-NH _{2 >} SEQ ID NO: 2, SEQ ID NO: 2-NH ₂ , SEQ ID NO: 3 and SEQ ID NO: 3-NH _? ,

(b) assaying the affinity of the peptide to the tissue or cells, and (c) assessing the degree of the assayed affinity using the functions of the expressing cells as an i ndi cation .

The above inventions of processes will be conveniently utilizable for researches of the receptors, screening of agonists on PACAP type 1 receptors, etc. According to the invention Of another, the fourth embodiment is provided a method for assessing the degree of disease associated with abnormalities in expression or structure of PACAP type 1 receptor in a tissue derived from a mammal , the method comprising steps of

(a) contacting a tissue or cells derived from each of normal animals and a test animal and predicted to contain the expressing cells with at least one pep¬ tide selected from the group consisting of peptides represented by SEQ ID NO: 1 , SEQ ID NO: 1-NH _{2 >} SEQ ID NO: 2, SEQ ID NO: 2-NH _? , SEQ ID NO: 3 and SEQ ID NO: 3-NH ₂ ,

(b) - assaying the affinity of the peptide to each tissue or cells, (c) mutual ly comparing the affinities of the peptide to the tissues or cells, and then

(d) assessing the degree of damage of the expressing cells in both kinds of the animals usi ng the difference in the degrees of the affi nities as an indi- c ati on .

According to the invention of this embodiment, the states of PACAP type 1 receptors or expressing cell s of the receptors can be assessed, and therefore, the i nvention wil l be utilizable for diagnosis of diseases caused by abnormali ty of these states .

According to the invention of another, the fifth embodiment is provided a method for, in PACAP type 1 receptor-expressi ng cel ls in a mammal , heightening the cyclic AMP production abi lity, increasing the intracel- lular calcium concentration, increasing the concentra¬ tion of inosi tol 3-phosρhate, or expanding the nervous processes, which comprises a step of administering to the mammal a peptide selected if rom the group consisting of peptides represented by SEQ ID NO: 1 , SEQ ID NO: 1 -NH ₂ , SEQ ID NO: 2 and SEQ ID NO: 2-NH ₂ .

According to the invention of another, the sixth embodiment is provided a method for, in PACAP type 1 receptor-expressi ng cel ls in a mammal , lowering the cyclic AMP production ability, lowering the concentra- tion of inosi tol 3-phosphate, or contracting the nervous processes, which comprises a step of administering to

the mammal a peptide represented by SEQ ID NO: 3 or SEQ ID NO: 3-NH ₂ .

The invention of these 5th and 6th embodiments can be utilized for prophylaxis and treatment of diseas- es caused by increasing or lowering of functions, par¬ ticularly cyclic AMP or inositol 3-phosphate production ability of PACAP type 1 receptor-expressing cells . As such diseases, there may be mentioned some kinds of encephalopath i es , for example, Alzheimer's disease, etc., taking such specificity into account that PACAP type 1 receptors are mainly expressed in cells in brains, which is different from the case of other sub¬ type receptor(s).

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a graph showing the resul ts of the binding assay of each peptide to each transfected COS cells. Lanes 1 to 4 are % total binding to PACAP type 1 receptor cDNA transfected COS cells, and li kewise, lanes 5 to 8 are values to PACAP type 2 and lanes 9 to 12 are values to PACAP type 3. In the drawing, CO represents control , and PACAP represents PACAP 38. In lanes 1 to

1 12255

44,, bbiinnddiinngg ooff I I MMAAXX iinn tthhee pprreesseennccee oorr aabbsseennccee ((ccoonn¬- trol) of peptides mentioned at the axis of ^: aabbscissa is a assssaayyeedd , and in lanes 5 to 12, binding of 125

I VIP is assayed

Fig. 2 is a graph showi ng the resul ts of the binding assay of NSP and MAX to PACAP type 1 receptor cDNA traπsfected COS cells. CO is total binding (con— t rol ) of labeled MAX in the absence of peptides.

Fig. 3 is a graph showing the assay resul ts of % of total binding to each transfected COS cells of M65 ,

PACAP 6-38, MAX and PACAP 38. As to PACAP type 1 , binding of [ 125 I]PACAP 27 in the presence or absence (control) of peptides mentioned at the axis of abscissa is shown, and as to PACAP types 2 and 3, binding in the

presence or absence (control) of each peptide mentioned at the axis of abscissa is shown. CO, 6-38 and PAC mean control . PACAP 6-38 and PACAP 38, respectively.

Fig. 4 is a graph showing the assay resul ts of cyclic AMP production in each transfected cells caused by stimulation with each peptide. The values are values on peptides mentioned at the axis of abscissa of the respective transfected cells. In the drawing, CO and PAC mean control and PACAP 38, respectively. Fig. 5 is a graph showing the assay resul ts of cyclic AMP production of PACAP type 1 receptor cDNA transfected COS cel ls caused by MAX and NSP.

Fig. 6 is a graph showing the blocking effects of M65 or PACAP 6-38 on PACAP 38 - stimulated cyclic AMP production. In the drawing, values on PACAP type 1 receptor cDNA transfected COS cells are shown in lanes 1 to 3, and values on type 2 and type 3 COS cells are shown in lanes 4 to 6 and lanes 7 to 9, respectively. Fig. 7 is a graph showing the inhibition ability of MAX and secretin family peptides on specific binding of MAX and PACAP 27 on the rat brain crude membrane. The values show % of speci fic binding of [ [ ¹¹²²⁵⁵ II]]MMAAXX a anndd [[ ¹¹²²⁵⁵ II]]PPAACCAAPP 2277 iinn tthe presence of peptides mentioned at the axis of abscissa

DETAILED DESCRIPTION OF THE INVENTION

"PACAP type 1 receptors" in the invention are membrane-bound proteins existing in encephalic tissues,, particularly brain hypothalami and pi tuitary glands of human beings, rats, etc. Since signi ficant difference in functions of PACAP type 1 receptors is not observed among animal species as far as the objects of the inven¬ tion is concerned, PACAP type 1 receptors can be used regardless of their origins. Cells wherein such PACAP type 1 receptors are expressed and methods for preparing the cel ls are known

per se , and for example, described in Pisgna J.R. et al . , Molecular cloning and functional expressions of the pituitary adenylate cyclase activating polypeptide type 1 receptor, Proc. Natl . Acad. Sci . USA. 90 (1993) 6245- 6249. On the other hand, as to PACAP type 2 (VIP human type 1) and PACAP type 3 (VIP human type 2) receptors, cDNA expression vectors encoding these receptors and their expression, etc. are described, for example, in Sreedharan, S.P., et al . , Biochem. Biophys. Res. Commun. 193 (1993) 546-553. Therefore, the receptors mentioned in the invention include not only those disclosed in these l iteratures, but those which are derived from other various mammals and can be prepared according to the description of these literatures. Peptides represented by SEQ ID NO: 1 and SEQ

ID NO: 1-NH ₂ (also referred to as "MAX" and "MAX-NH ₂ ", respectively. The latter means that amidation (-C0NH- ) is made by that C-terminal amino acid residue of MAX, i .e. , Lys is removed and Gly is converted to -NH _? . Hereinafter, analogous expressions have similar mean¬ ings) are known per se (see, U.S. Patent No. 5,480,864) . Further, as peptides represented by SEQ ID NO: 2 and SEQ ID NO: 3, and SEQ ID NO: 2-NH _? and SEQ ID NO: 3-NH ₂ (referred to as NSP, M65, NSP-NH ₂ and M65-NH ₂ , respec- tively) . those disclosed in U.S. Serial No. 08/540,033 can be used.

According to the invention, MAX, MAX-NH. , NSP, NSP-NH ₂ , M65 AND M65-NH ₂ have ^speci f i c affi nity (or binding) to the surfaces of cul ture cells expressing cDNA encoding the PACAP type 1 receptor. Having specif¬ ic affi nity to PACAP type 1 receptors means that they do not exhibit affinity to PACAP type 2 receptors and PACAP type 3 receptors, and exhibit affinity only to PACAP type 1 receptors. Specific examples of binding condi- tions are described later.

Thus, according to the invention, by contact-

i ng a tissue or cel ls derived f rom a mammal with such a peptide , and assayi ng the bindi ng abi lity of the peptide to the tissue or cells, i t is possibl e to know whether or not PACAP type 1 receptor-expressi ng cel ls exi st in the tissue or cells to be tested. Such contact i s usually conducted by incubating the tissue or cul ture cells at temperatures having no bad i nfluence on the cells (e.g. , 4X ) for several hours (e.g. , 1 to 2 hours) . Assay of the binding ability can be conducted by using as such a peptide to be used one l abeled with a

125 13 3 radioisotope (e.g. , I , C and H) , and measuring its binding amount by a gamma counter or the li ke, if neces¬ sary af ter a usual preliminary treatment.

Mammals mentioned in the invention include all animals regardless of their species so long as they have cells capable of expressi ng PACAP type 1 receptors, and as examples thereof , there can be mentioned rats, rab¬ bits, guinea pigs, cattle , human beings, etc.

All the above-mentioned MAX, MAX-NH. , NSP, NSP-NH ₂ , M65 and M65-NH ₂ specif ically bind to PACAP type 1 receptor-expressi ng cel ls, and do not bind to PACAP type 2 and PACAP type 3 receptor-expressing cells . Therefore, when a tissue or cel ls tested have PACAP receptors, it is possible to judge whether the receptors belong to subtype 1 or not, by assayi ng the bindi ng ability of the peptides thereto , and/or assaying a form expressed when the binding information is transmi tted, for example, i ncrease of the intracel lular cyclic AMP concent rati on increase of the intracellular calcium concentration increase of the inositol 3-phosphate concent rati on or -a change of the cel lular form such as expansi on of nervous processes. Further, when the binding test is conducted on cells having PACAP type 1 receptors, or a tissue or cells containing the cells, i t i s possible to assess functions of the receptor-ex¬ pressing cell s by checking the binding amount, and/or

intensi ty of the phenotype of the information transmis¬ sion. Further, by conducting the binding test on PACAP type 1 receptor-expressing cells derived from healthy (normal ) animals and the expressing cells derived from a test animal , and comparing the binding amount and/or change of the phenotype of the information transmission , i t is also possible to assess whether or not altered physiology exists in the expressing cells derived from the test animal or whether injury is caused or not t herei n .

When cells having PACAP type 1 receptors (or expression cells) are stimulated with MAX, MAX-NH. , NSP or NSP-NH ₂ according to the invention , the stimul ated cells produce cyclic adenosine 3 ' , 5 ' -monoph osphat e (referred to as "cyclic AMP" or "cAMP" in the specifica¬ tion), and further, show the phenotypes that result from such binding and signaling. Namely, the peptides have agonizing binding ability on cells having PACAP type 1 receptors (PACAP type 1 receptor-expressing cells). Stimulation of PACAP type 1 receptor-expressing cells can usually be made by incubating the cells in medium (e.g. , DMEM, HANKS) in the presence of such a peptide at a temperature of about 37T; for 10 and several mi nutes (e.g. , about 10 minutes). Cycl ic AMP, calcium and inositol 3-phosphate produced can be detected by measur¬ ing methods known per se . For example, their measure¬ ment is conveniently conducted using, for example an Amersham cycl ic AMP detection system (Amersham, Arlington Heights, IL). Namely, according to the invention, since

PACAP type 1 receptor-expressing celTs produce cyclic AMP by stimulation with any one peptide of MAX, MAX-NH ₂ , NSP and NSP-NH ₂ , by detecting the producing abili ty, and/or detecting or observing the ρhenotype(s) of the information transmission, it is possible to determine whether or not a certain tissue or cells contain PACAP

type 1 receptor-expressing cells. When this distin¬ guishing method is combined with the assessment of affinity (or binding abil ity) to the cells of the men¬ tioned peptides, it is possible to determine more accu- rately whether or not PACAP type 1 receptor-expressing cells exist i n the tested tissue or cells.

Since MAX, MAX-NH _? , NSP and NSP-NH _j not only do not bind to either of PACAP type 2 and PACAP type 3 receptor-expressing cells, but do not induce production of cycl ic AMP, it i s possible to clearly distinguish type 1 among PACAP receptor subtypes.

Further, by combining the detection resul ts of the cyclic AMP production abili ty of PACAP type 1 receptor-expressing cells based on stimulation of the expressing cells wi th peptide(s) such as MAX with the assessment of the binding abili ty of the peptide(s) to the expressing cell s, it comes to be possible to assess functions of the expressing cel ls in the tested tissue or cells more accurately. This assessment system will , for example, be useful for assessing influence which the environment where the PACAP type 1 receptor-expressing cells are placed has on the cel ls. For example, since influence whi ch a compound has on the expression system can be examined by applying thi s assessment system to a competi tion test, i t will be possible to screen novel agonists or antagonists to PACAP type 1 receptors.

Still further, when functions of PACAP type 1 receptor-expressing cells derived from healthy, animals and functions of the expressing cells derived from a test animal are compared using a combination of intensi¬ ty of. the binding ability with intensity of the cyclic AMP production abil ity as a measure, it will be possible to examine more accurately whether the expressing cells derived from the test animal are normal or have some abnormality. When it is taken into account that PACAP type 1 receptor-expressing cell s mainly exist in ence-

phalic cells, the method by the invention may be uti¬ lized for diagnosis of some encephalic disorder.

According to the invention, i t was found that M65 and M65-NH- ant agoni z i ngl y act on PACAP type 1 receptors. Namely, M65 and M65-NH. have specific bind¬ ing ability to type 1 among subtypes of PACAP receptors , but do not induce cyclic AMP production of cells having the receptors. Thereby, they inhibit the binding action of MAX. MAX-NH ₂ , NSP and NSP-NH ₂ . and PACAP 38 and PACAP 27, which bind to PACAP type 1 receptor-expressing cells and induce production of cyclic AMP, to the expressing cells.

Thus, according to the invention, i t is possi¬ ble to assess functions and extent of injury of PACAP type 1 receptor-expressing cells, by using a combination of any of, fi rstly, bindi ng abi lities of PACAP 38 and PACAP 27, which are not specific to PACAP type 1 recep¬ tors (i .e. , exhibit affinity also to type 2 and type 3) , to PACAP type 1 receptor-expressing cells, and bi nding abilities of MAX, MAX-NH ₂ , NSP and NSP-NH ₂ to the ex¬ pressing cells with inhibition ability of M65 or M65-NH. to the binding abil ity as a measure. Such inhibi tion ability can be investigated by detecting binding ability of M65 or M65-NH. to cells to be tested, in the presence of a peptide selected from the group consisting of PACAP 38, PACAP 27, MAX, MAX-NH ₂ , NSP and NSP-NH ₂ , or by de¬ tecting binding ability of PACAP 38, etc. under a re¬ verse circumstance. In this occasion , a peptide belong¬ ing to any group is labeled with a radioisotope (e.g. ,

125 I) and used, or alternativel y, any of the above- mentioned phenotypes of the information transmission is used as an indication.

Incidentally, since PACAP was found in 1989 by Arimura et al . (Biochem. Biophys. Res . Commun. 164, 567-574 (1989)), it has been revealed that its actions range widely, for example that PACAP has a nervous

process expansion action (Deutsch, L. et al . , J. Biol . Chem. 267. 5108-5113 (1992), and an action as a cell proliferation enhancer in some kind of tumor cell s (Buscai l , L. et al . , (1992) Gas t roent erol og y 103, 1002-1008) . When these are taken into account, there is a possi bility that MAX, MAX-NH ₂ , NSP and NSP-NH ₂ having specificity to PACAP type 1 receptors can be used as medicaments for -increasing functions of particularly encephalic cells, and M65 and M65-NH. can be used as medicaments for inhibiting the action of compounds having a bad influence on PACAP type receptor-expressing cells.

Therefore, according to the invention, it may be possible to prevent or treat diseases caused by lowering or abnormal increase of functions of the ex¬ pressing cells, by admini stering the peptides to ani¬ mals. When these peptides are administered to animals, there may be utilized a method which comprises di rectly i njecting them, if necessary together with suitable carriers, into the affected part, or other methods usually used for administration of medicaments.

Three-letter symbols used on α-amino acids for describing the invention are based on the followi ng abbrevi ations commonly used in the art.

Common name Three-letter symbol

Al ani n e Al a Argi ni ne Arg

Asparagine Asn

Aspartic acid Asp

Cystei ne Cys

Glutamine Gin Glutamic acid Glu

Glycine Gly

Hi sti d i ne His

Isoleucine lie

Leuci n e Leu Lysine Lys

Methionine Met

Phenylalanine Phe

Prol i ne Pro

Serine Ser Threonine Thr

Tryptophan Trp

Tyrosi ne Tyr

Val i ne Val

EXAMPLES

The invention is illustrated below mentioning specific examples of actions of peptides according to the invention on PACAP type 1 receptors, and type 2 and type 3 receptors, but the true scope is now particularly pointed out in the appended claims.

Materials and methods

Peptides: MAX (SEQ ID NO: 1) and MAX-NH _j were prepared according to U.S. Patent No. 5,480,864. NSP (SEQ ID NO: 2) and NSP-NH ₂ , and M65 (SEQ ID NO: 3) and

M65-NH- were prepared according to the method described

in U.S. Serial No. 08/540,033. These peptides can also be prepared by peptide synthesis based on the disclosed sequences. Labeling of these peptides with ^{1 Z5} ι _was conducted by Amersham custom labeling service department (specific activity on each peptide: about 2000 Ci/ mmol). PACAP 38 (SEQ ID NO: 4-NH ₂ ) , PACAP 27 (SEQ ID NO: 5-NH ₂ ), PACAP 6-38 (SEQ ID NO: 6-NH ₂ ) and PACAP 6-27 (SEQ ID NO: 7-NH ₂ ), and GRF, glucagon, secretin and PHI were purchased from Peninsula (Belmont, CA) . Further, iodinated PACAP 27 and VIP were purchased f rom Dupont and Amersham, respectively.

Receptor: PACAP rat type 1 cDNA was obtained f rom Dr . Joseph R. Pisegna, National Institute of Diabe¬ tes, Digestive and Kidney Diseases, NIH. PACAP human type 2 and type 3 (VIP human type 1 and type 2) c DNA were obtained from Dr. Sunil P. Sreedharan, Division of Allergy & Immunology, UCS F . Transfection with c DNA

COS cells were sown one day before transfection in 6-wel 1 dishes containing complete DMEM medium (DMEM with 10% FCS, penicillin and streptomycin) . COS cel ls in wells were transfected with each cDNA, respectively, according to a DEAE-dextran method using standard procedure. These cells incubated at 37*C for 3 hours, and then the medium in each well was removed. These cells were treated with 10 % dimethyl sulfoxide (DMSO) in complete DMEM medium for 2.5 minutes. After removal of the 10 % DMSO solution, the fresh complete medium was added, and 3 days later, these cells were used for assay.

Binding of Peptide-s

Proli ferated cells of the PACAP type 1 , type 2 and type 3 receptor-expressing cells, prepared as above, were incubated together with each peptide as follows at 4°C for 2 hours, and then binding amounts of the peptides to the cel ls were measured.

(1) Each confluent transfected cells on the 6-well plates were contacted with each peptide by incu¬ bating the cells in a medium (DMEM) in the presence or absence of 1 μM of unlabeled MAX, PACAP 38 or VIP at 4*C for 2 hours using 70 pM [ ¹²⁵ I]MAX for PACAP type 1 transfected cells, and 70 pM each of [ ¹²⁵ I] VIP for PACAP type 2 and type 3 transfected cells. At the end of incubation, each of the resultant broths was filtered under reduced pressure by passing it through a GF/C Whatman glass microfiber filter pretreated with 0.5 % pol yethylene- imi ne . Each cell culture was washed three times with 3 ml portions of the medium at 4°C . The radioactivity trapped on each filter was measured using a gamma counter (MINIGAMMA (LKB-Wallac, Turku, Fi n- land)). Each measured values were recorded as a mean value (mean ± standard deviation) in tripricate deter¬ minations of binding amounts of each labeled peptide to the type 1 transfected cells. The results of % total binding obtained by making conversion thereof supposing the total binding in the case where any unlabeled pep¬ tide does not exist (control) to be 100 % total binding are shown in Fig. 1.

It is understood from Fig. 1 that MAX has specific affinity to PACAP type 1 receptors. (2) Binding assay of NSP to PACAP type 1 receptor cDNA transfected cells was conducted in the same manner as in the above (1) . Binding of 70 pM

125 [ I]NSP to the COS cells was measured in the presence. or absence (control ) of 1 μM of NSP or MAX as an unla- bθled peptide. The results are shown in Fig. 2. Values are means ± standard deviations of triplicate determi- - nations .

It is understood from Fig. 2 that NSP exhibits binding to PACAP type 1 receptors almost equal to that of MAX.

(3 ) % of t otal b i ndi ng of 70 pM [ ^{1 2 5} I ]MAX

(PACAP type 1 transfected cells) or 70 pM [ ¹²⁵ I]VIP (PACAP type 2 and 3 transfected cells , respectively) was measured in the presence of 1 μM peptides ( M65 , PACAP 6-38 and MAX for type 1 ; M65 , PACAP 6-38 and PACAP 38 for types 2 and 3) in place of MAX, PACAP 38 and VIP in the above (1) . The measured values were recorded as relative mean values calculated when the measurement result in the abβence of the peptides (control) was supposed to be 100 %. Values are means ± standard deviations of tripl icate determinations. The results a re shown in Fig. 3.

It is seen from Fig. 3 that M65 exhibits binding to PACAP type 1 receptors equal to that of MAX. Measurement of cycl ic AMP In the same manner as above, COS cells trans¬ fected with each cDNA were prol iferated up to confluence i n 24-well pl ates each containing HANKS medium wi th 1 mM 3-i sobu tyl -1 -methyl xanthine and 0.1 % bovine serum albumin (BSA) . Then, the proli ferated cells were stimu- 1 ated by incubating them together with 100 nM each of the peptides at 37°C for 10 minutes. The test wherein no peptide was used was used as control . The incubation was terminated by aspiration of the medium and addition of 400 μl ice-cold 50 mM Tris, 4 mM EDTA, pH 7.5. The cells were harvested and transferred to 1.5-ml Eppendorf tubes. The cells were boiled therein for 5 minutes and then spined for 5 minutes . The supernatants were col¬ lected and 50 μl al iquots were-taken for assay of cyclic AMP using Amersham cyclic AMP detection system. (1) The results of stimulation of PACAP type

1 receptor cDNA transfected cel ls with MAX, PACAP 38 and VIP (lanes 1-4), and the results of stimulation of PACAP type 1 and 2 receptor cDNA transfected COS cells with each peptide (lanes 5-8 and 9-12. control does not contains any peptide) were shown in Fig. 4. Values are means ± standard deviations of tripli cate determi na-

t i ons .

(2) Cyclic AMP production in PACAP type 1 cDNA transfected COS cells using MAX and NSP was assayed in the same manner as in the above (1 ). The results are shown in Fig . 5.

It is seen from Fig. 4 that MAX brings about cyclic AMP production by PACAP type 1 receptor cDNA transfected cells almost equal to that brought about by PACAP 38, but does not induce cyclic AMP production by type 2 and 3 receptor cDNA transfected cells, although PACAP 38 brings about cyclic AMP production by the type 2 and 3 cells equal to that brought about by VIP. It is seen from Fig. 5 that NSP brings about cyclic AMP pro¬ duction characteristics equal to that brought about by MAX.

Blocking Effect of M65 and PACAP 38 on the PACAP 38 stimulated cyclic AMP Production

Blocking effect of M65 and PACAP 6-38 on PACAP 38 stimulated cyclic AMP production in PACAP type 1 , type 2 and type 3 receptor cDNA transfected COS cells was assayed.

The transfected COS cel ls were incubated together with 1 nM PACAP 38 at 37°C for 10 minutes in the presence of 10 μM M65 or PACAP 6-38, and cycl ic AMP production of each cells was assayed. Assay of cyclic AMP was conducted by Amersham cyclic AMP detection system. Relative cyclic AMP production was recorded obtained when the result in the absence of M65 or PACAP 6-38 (control ) was supposed to be 100 %. The results are shown in Fig. 6. Values are means ± standard devia¬ tions of duplicate determinations.

It is seen from Fig. 6 that, as to blocking effect of peptides on PACAP 38 stimulated cyclic AMP production, M65 exhibits stronger blocking on PACAP type 1 receptor cDNA transfected COS cells than PACAP 6-38 which is an antagonist of PACAP 38, but does not sub-

stantially block cyclic AMP production by the type 3 receptor cDNA transfected COS cells.

As understood from the above, M65 seems to act as a specific antagonist to PACAP type 1 receptors of PACAP 38.

It is ascertained that MAX-NH ₂ , NSP-NH ₂ and M65-NH ₂ correspondi ng to MAX, NSP and M65 , respectively, have the same actions as mentioned above.

125 Inhibition of speci fic bi nding of [ I)MAX and [ ^12S I]PACAP 27 to rat brain

(1) Preparation of membranes

Rat brain tissue from which the cerebellum was removed was placed in 10 volumes of i ce-cold 50 mM Tris-HCI buffer (pH 7.6) contai ning 0.32 M sucrose, 5 mM EDTA, 1 μg/ml leupeptin, 1 μg/ml pepstatin A, 2 μg/ml bacitracin and 10 μg/ml p henylmethyl s ul f ony 1 fluoride. The tissue was homogenized with a plytron PT 3000 (Brinkmann Instruments, Westbury, NY) for 30 seconds at power level 7 at 4°C . The homogenate was centrifuged for 10 minutes at 1 ,000 x g at 4T) . The supernatant was removed , and the pellet was resuspended in 15 ml of homogenizing buffer, homogenized again using the Polytron at the same setting as the first homogeniza¬ tion, and the homogenate was centrifuged at 1 ,000 x g for 10 minutes at 4°C . The combined supernatant was centrifuged at 30,000 x g for 45 minutes at 4°C . The pellet was washed two times by successive resuspension i n 50 mM Tris-HCI buffer contai ning 1 mM MgCl ₂ , 0.3 % BSA, 1 μg/ml leupeptin, 1 μg/ml pepstatin A, 2 μg/ml bacitracin and 10 μg/ml p henyl methyl s ul fony 1 fluoride.

(2) Binding of [ ^{, 2} - ⁵ I]MAX and PACAP 27 Crude membranes (250-400 μg) were incubated for 1 hour at 22°C in a final volume of 0.5 ml consist¬ ing of 50 mM Tris-HCI buffer (pH 7.6) containing 0.3 % BSA, 1 mM MgCl ₂ , 1 μg/ml leupeptin, 1 μg/ml pepstatin A, 2 μg/ml bacitracin, 10 μg/ml phenyl me thyl su 1 f onyl fluo-

125 ride and 50 pM [ I]MAX in the absence or presence of 1 μM MAX. At the end of incubation, samples were assayed for protein-bound radioactivity by vacuum filtration through GF/C Whatman glass microfiber filters pretreated with 0.5 % po 1 ythlenimi ne . Fil ters were then washed with 3 x 3 ml of incubation buffer at 4°C . The radioac¬ tivity trapped on the fil ters was measured using a gamma

125 counter. Non-specific [ I]MAX and- PACAP 27 binding was determined by the addition of 1 μM unlabeled MAX, PACAP 38, PACAP 27, VIP, GRF, glucagon, secretin and PHI, respectively. In the results, specifi c binding (total cpm minus non-specific cpm) is shown . Proteins or peptides were estimated by the method of Bradford using bovine serum albumin as standard. The results are shown i n Fig. 7. Values are means ± standard deviations of triplicate determinations.

It is seen from Fig. 7 that any of secretin family peptides other than PACAP 27 and PACAP 38 does not inhibit either specific [ ¹²⁵ I]MAX or [ ^{1 25} I]PACAP 27 binding to rat brain.

(3) The ligand specificity of the rat brain PACAP receptor (or MAX receptor) was investigated by analyzing competition abi lity of various peptides, i .e. , MAX, M65, PACAP 38, PACAP 27, PACAP 6-38, PACAP 6-27 and VIP with f ¹²⁵ I]MAX and [* ²⁵ I ] PACAP bi ndi ng , according to the binding assay of the above (2). Displacement pat¬ terns on [ ¹²⁵ I]MAX and [ ^{1 25} I]PACAP 27 were analogous. I C _j . « values, on the various peptides are shown in the foi 1 owi ng Tab 1 e 1

Table 1

Relative affini tes of the PACAP receptor in rat brain crude membrane for various peptides

Peptide [[ ¹ ' ² " ⁵ " I1]3MMAAXX [ ^{12 5} IjPACAP 27

MAX 1,14± 0.07 3 .35± 0, .29 M65 2.96± 0.54 5 .96± 0. .71 PACAP 38 1 .91± 0.13 4 .45± 0. .22

PACAP 6-38 8.35± 2.04 39. .14± 3. .00

PACAP 27 2.16± 0.45 9 .55± 0, .75

PACAP 6-27 234.6 ± 56.2 1031. .3 ± 63. .0

It is seen from Table 1 that the af fini ty of M65, an antagonist of MAX , is very cl ose to the affinity of PACAP agonists (e.g.. MAX, PACAP 27 and PACAP 38) . PACAP 6-38, a PACAP antagonist, exhibits IC,. val ues of 8.35 nM and 35.14 nM on [ ¹²⁵ I]MAX and [ ¹²⁵ I]PACAP 27, respectively, and these values are about 6-10 times higher than the val ues exhibi ted by M65. I C, » of PACAP 6-27 is much higher than the value by M65. These data shows a possi bility that M65 is very useful as a PACAP type 1 specif ic antagonist.

SEQUENCE LISTING

INFORMATION FOR SEQ ID NO: 1 :

(i ) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 67 amino acids

(B) TYPE : ami no aci d

(C) TOPOLOGY: linear

(i i) MOLECULE TYPE: pepti de

(xi ) SEQUENCE DESCRIPTION: SEQ ID NO: 1 :

Gly Ser lie Leu Cys Asp Ala Thr Cys Gin Phe Arg Lys Ala He Asp 16

1 5 10 15

Asp Cys Gin Lys Gin Ala His His Ser Asn Val Leu Gin Thr Ser Val 32

20 25 30

Gin Thr Thr Ala Thr Phe Thr Ser Met Asp Thr Ser Gin Leu Pro Gly 48

35 40 45

Asn Ser Val Phe Lys Glu Cys Met Lys Gin Lys Lys Lys Glu Phe Lys 64

50 55 60

Ala Gly Lys 67

65

INFORMATION FOR SEQ ID NO: 2:

(i ) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 61 amino acids

(B) TYPE : ami no aci d

(C) TOPOLOGY: linear

(i i) MOLECULE TYPE: pepti de

(xi ) SEQUENCE DESCRIPTION: SEQ ID NO: 2:

Gly Ser Gly Gin Phe Arg Lys Ala He Asp Asp Cys Gin Lys Gin Ala 16

1 5 10 15

His His Ser Asn Val Leu Gin Thr Ser Val Gin Thr Thr Ala Thr Phe 32

20 25 30

Thr Ser Met Asp Thr Ser Gin Leu Pro Gly Asn Ser Val Phe Lys Glu 48

35 40 45

Cys Met Lys Gin Lys Lys Lys Glu Phe Lys Ala Gly Lys 61

50 55 60

INFORMATION FOR SEQ ID NO : 3:

(i ) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 46 amino acids

(B) TYPE: ami no aci d

(C) TOPOLOGY: linear

(i i) MOLECULE TYPE: peptide

(xi ) SEQUENCE DESCRIPTION: SEQ ID NO: 3:

Gly Ser Cys Asp Ala Thr Cys Gin Phe Arg Lys Ala He Asp Asp Cys 16

1 5 10 15

Gin Lys Gin Ala His His Ser Asn Val Pro Gly Asn Ser Val Phe Lys 32

20 25 30

Glu Cys Met Lys Gin Lys Lys Lys Glu Phe Lys Ala Gly Lys 46

35 40 45

INFORMATION FOR SEQ ID NO: 4:

(i ) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 38 amino acids

(B) TYPE : ami no aci d

(C) TOPOLOGY: linear

(i i) MOLECULE TYPE: peptide

(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 4:

His Ser Asp Gly He Phe Thr Asp Ser Tyr Ser Arg Tyr Arg Lys Gin

1 5 10 15

Met Ala Val Lys Lys Tyr Leu Ala Ala Val Leu Gly Lys Arg Tyr Lys

20 25 30

Gin Arg Val Lys Asn Lys 35

INFORMATION FOR SEQ ID NO: 5:

(i ) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 27 amino acids

(B) TYPE : ami no aci d

(C) TOPOLOGY: linear

(i i) MOLECULE TYPE: peptide

(xi ) SEQUENCE DESCRIPTION: SEQ ID NO: 5:

His Ser Asp Gly He Phe Thr Asp Ser Tyr Ser Arg Tyr Arg Lys Gin

1 5 10 15

Met Ala Val Lys Lys Tyr Leu Ala Ala Val Leu 20 25

INFORMATION FOR SEQ ID NO: 6:

(i ) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 33 amino acids

(B) TYPE : ami no aci d

(C) TOPOLOGY: linear

(i i ) MOLECULE TYPE: pepti de

(xi ) SEQUENCE DESCRIPTION: SEQ ID NO: 6:

Phe Thr Asp Ser Tyr Ser Arg Tyr Arg Lys Gin Met Ala Val Lys

1 5 10 15

Lys Tyr Leu Ala Ala Val Leu Gly Lys Arg Tyr Lys Gin Arg Val

20 25 30

Lys Asn Lys

INFORMATION FOR SEQ ID NO : 7:

(i ) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 22 amino acids

(B) TYPE : ami no aci d

(C) TOPOLOGY: linear

(i i ) MOLECULE TYPE: pepti de

(xi ) SEQUENCE DESCRIPTION: SEQ ID NO: 7:

Phe Thr Asp Ser Tyr Ser Arg Tyr Arg Lys Gin Met Ala Val Lys 1 5 10 15

Lys Tyr Leu Ala Ala Val Leu 20