Table 2.
VPAC1R, VPAC2R, or PAC1R selective peptide analogues.
| Selective Receptor | Compound | Agonist/Antagonist | Peptide Modifications | Relative Selectivity * | Reference |
|---|---|---|---|---|---|
| VPAC1R | [Tyr9,Dip18]-VIP | Agonist | VIP analogue | VPAC1R ([125I]VIP Ki = 0.1 nM) VPAC2R ([125I]VIP Ki = 53 nM) PAC1R ([125I]PACAP27 Ki = 3 μM) |
[140] |
| [Ala22]-VIP | Agonist | VIP analogue | VPAC1R ([125I]VIP IC50 = 10 nM), VPAC2R ([125I]RO 25-1553 IC50 = 1 μM) |
[141,142] | |
| [Leu22]-VIP | Agonist | VIP analogue | VPAC1R ([125I]VIP IC50 = 11 nM), VPAC2R ([125I]RO 25-1553 IC50 = 700 nM) |
[143] | |
| [Ala11,22,28]-VIP | Agonist | VIP analogue | VPAC1R (cAMP EC50 < 1 nM) VPAC2R (cAMP EC50 > 1 µM) |
[142] | |
| [Arg16]-PACAP (1–23) | Agonist | C-terminal truncated PACAP analogue | VPAC1R ([125I]VIP IC50 = 2.5 nM), VPAC2R ([125I]RO 25-1553 IC50 = 1.2 µM) |
[143] | |
| Chicken [Arg16]-secretin | Agonist | Secretin analogue | PAC1R ([125I]Ac-His1-PACAP27 IC50 = 30 µM) VPAC1R ([125I]VIP IC50 = 100 nM), VPAC2R ([125I]VIP IC50 = 10 µM) 1 |
[144] | |
| [Lys15, Arg16, Leu27]-VIP(1-7)/GRF(8-27) | Agonist | Chimeric VIP/GRF analogue | VPAC1R ([125I]VIP IC50 = 1 nM), VPAC2R ([125I]VIP IC50 > 30 µM) 2 |
[144] | |
| PG 97-269 | Antagonist | N-terminal modified VIP/GRF chimeric analogue | VPAC1R ([125I]VIP IC50 = 2 nM), VPAC2R ([125I]VIP IC50 = 3 μM) |
[145] | |
| VPAC2R | RO 25-1392 | Agonist | Cyclic VIP analogue | VPAC1R ([125I]VIP Ki = 1 μM), VPAC2R ([125I]VIP Ki = 9.6 nM) |
[146] |
| RO 25-1553 | Agonist | Cyclic VIP analogue | VPAC1R ([125I]VIP IC50 = 800 nM), VPAC2R ([125I]RO 25-1553 IC50 = 1 nM) |
[147] | |
| PG 96-249 | Agonist | Linear RO 25-1553 analogue | VPAC1R ([125I]VIP IC50 = 3 μM), VPAC2R ([125I]RO 25-1553 IC50 = 10 nM) |
[147] | |
| BAY 55-9837 | Agonist | PACAP/VIP analogue | PAC1R ([125I]PACAP27 IC50 = N/A) 3 VPAC1R ([125I]PACAP27 IC50 = 8.7 µM), VPAC2R ([125I]PACAP27 IC50 = 60 nM) |
[34] | |
| PG 99–465 | Antagonist | N-terminal myristoylated, C-terminal elongated VIP analogue | VPAC1R ([125I]VIP IC50 = 200 nM), VPAC2R ([125I]RO 25-1553 IC50 = 1 nM) |
[147] | |
| PAC1R | M65 | Antagonist | Maxadilan analogue | PAC1R ([125I]PACAP27 Kd = 0.6 nM), VPAC1R ([125I]VIP Kd = N/A), VPAC2R ([125I]VIP Kd = N/A) 4 |
[133] |
| max.D.4 | Antagonist | Maxadilan analogue | PAC1R ([125I]PACAP27 Kd = 0.6 nM), VPAC1R ([125I]VIP Kd = N/A), VPAC2R ([125I]VIP Kd = N/A) 4 |
[148] | |
| PACAP(6-38) | Antagonist | N-terminal truncated PACAP analogue | PAC1R ([125I]Ac-His1-PACAP27 Ki = 30 nM), VPAC1R ([125I]VIP Ki = 600 nM), VPAC2R ([125I]Ac-His1-PACAP27 Ki = 40 nM) 5 |
[149,150] |
* The radioligand used is specified for radioligand binding assays. 1 Human VPACRs and rat PAC1R used for the assay. 2 Selectivity for growth hormone-releasing factor (GRF) receptor was not tested. 3 For BAY 55-9837, no competitive binding was observed for PAC1R. 4 For max.D.4 and M65, competition of [125I]PACAP27 and [125I]VIP binding to the VPAC receptors was not observed. 5 Also displays significant affinity for VPAC2R [149,150,151].