TABLE 4.
The potency of various multi-substituted PACAP-related analogs for PAC1-R, VPAC1-R and VPAC2-R.
| Peptide Number | Peptide structure | [3H]cAMP |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| PAC1-R |
VPAC1-R |
VPAC2-R |
|||||||
| PAC1-R |
VPAC1-R/PANC-1 |
T47D |
VPAC2-R/PANC-1 |
||||||
| % max | EC50 (nM) | % max | EC50 (nM) | % max | EC50 (nM) | % max | EC50 (nM) | ||
| PACAP27 | Ag | 0.03 ± 0.00 | Ag | 0.20 ± 0.01 | Ag | 0.79 ± 0.07 | Ag | 1.00 ± 0.04 | |
| PACAP38 | Ag | 0.03 ± 0.03 | Ag | 0.54 ± 0.05 | Ag | 3.24 ± 0.19 | Ag | 1.38 ± 0.10 | |
| VIP | No Act | 174 ± 10 | Ag | 0.18 ± 0.01 | Ag | 1.00 ± 0.07 | Ag | 1.50 ± 0.07 | |
| P48 | [Iaa1 ,d-Ser2,Ala22]PACAP38 | Ag | 2.19 ± 0.17 | Ag | 83 ± 9 | Ag | 501 ± 27 | Ag (1 µM, 43) | >1,000 |
| P49 | [Iaa1,d-Tyr2,Ala22]PACAP38 | Ag | 98 ± 2 | Ag | 389 ± 33 | Ag (1 µM, 54) | 832 ± 63 | Ag | 501 ± 36 |
| P51 | [Iaa1,d-Ala2,Ala22]PACAP38 | Ag | 9.12 ± 0.67 | Ag | 20.4 ± 1.5 | Ag | 7.10 ± 0.47 | Ag | 323 ± 20 |
| P29 | [Iac1,Ala16,17,d-Lys38]PACAP38 | Ag | 0.05 ± 0.00 | Ag | 1.45 ± 0.08 | Ag | 7.08 ± 0.44 | Ag | 2.53 ± 0.07 |
| P28 | [N-Ac-His1,Ala16,17,d-Lys38]PACAP38 | Ag | 0.09 ± 0.01 | Ag | 0.95 ± 0.12 | Ag | 7.08 ± 0.71 | Ag | 3.02 ± 0.10 |
| P8 | [N-Ac-His1,Pip3,Aib16,Ala17]PACAP27 | No Act | >1,000 | pAg (24) | >1,000 | No Act | >1,000 | Ag (1 µM, 13) | >1,000 |
| P39 | [Pip3,Ala14,17,Aib16,28,Lys34,d-Lys38]PACAP38 | Ag (1 µM, 14) | >1,000 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 |
| P38 | [Pip3,Ala15,17,Aib16,28,Lys34,d-Lys38]PACAP38 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 |
| P7 | [Pip3,Aib16,Ala17]PACAP27 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 |
| P35 | [Pip3,Aib16,28,Ala17,Lys34,d-Lys38]PACAP38 | Ag (1 µM, 81) | 407 ± 20 | Ag (1 µM, 48) | >1,000 | No Act | >1,000 | Ag (1 µM, 33) | >1,000 |
| P41 | [Pip3,Aib16,28,Ala17,20,Lys34,d-Lys38]PACAP38 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 |
| P40 | [Pip3,Aib16,28,Ala17,21,Lys34,d-Lys38]PACAP38 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 |
| P21 | [β-Ala3,Ala16,17]PACAP38 | Ag (1 µM, 61) | 602 ± 37 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 |
| P20 | [Hyp3,Ala16,17]PACAP38 | Ag | 139 ± 10 | pAg (25) | >1,000 | No Act | >1,000 | Ag (1 µM, 35) | >1,000 |
| P31 | [Hyp3,Aib16Ala17,Lys34]PACAP38 | Ag | 1.51 ± 0.10 | Ag (1 µM, 80) | 155 ± 13 | Ag (1 µM, 55) | >1,000 | Ag | 155 ± 11 |
| P33 | [Me-Asp3,Aib16,28,Lys34,d-Lys38]PACAP38 | Ag | 1.00 ± 0.06 | Ag | 16.2 ± 1.3 | Ag | 47.9 ± 2.6 | Ag | 23.4 ± 0.9 |
| P37 | [Ini3,Aib16,28,Ala17,Lys34,d-Lys38]PACAP38 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 |
| P36 | [Nip3,Aib16,28,Ala17,Lys34,d-Lys38]PACAP38 | Ag (1 µM, 39) | >1,000 | No Act | >1,000 | No Act | >1,000 | No Act | >1,000 |
| P32 | [Ala15,17,Aib16,28,Lys34,d-Lys38]PACAP38 | Ag | 1.38 ± 0.07 | Ag | 1.95 ± 0.16 | Ag | 30.2 ± 2.9 | Ag | 7.41 ± 0.39 |
| P23 | [Ala16,17,d-Lys38]PACAP38 | Ag | 0.35 ± 0.02 | Ag | 3.80 ± 0.33 | Ag | 12.9 ± 1.0 | Ag | 5.37 ± 0.36 |
| P30 | [Aib16,Ala17,Lys34]PACAP38 | Ag | 0.25 ± 0.02 | Ag | 1.38 ± 0.21 | Ag | 3.24 ± 0.24 | Ag | 3.80 ± 0.18 |
| P34 | [Aib16,28,Ala17,Lys34,d-Lys38]PACAP38 | Ag | 0.19 ± 0.01 | Ag | 1.58 ± 0.08 | Ag | 30.2 ± 1.9 | Ag | 2.63 ± 0.15 |
cAMP generation was determined in the indicated cell type loaded with [3H]adenine for 48 hours as described under Materials and Methods. Results are expressed as a percentage of the maximal stimulation of cAMP accumulation caused by 10 µM PACAP38, which was calculated using the curve-fitting program KaleidaGraph. The EC50 was calculated as the concentration causing half-maximal stimulation with each analog. In each experiment, each value was determined in duplicate, and values given are and means S.E.M. from at least three separate experiments. Abbreviations: see Fig. 1, Table 1 and Table 2 legends.