TABLE 1

Pharmacological and molecular characteristics of VIP/PACAP receptors

Receptor subtypeLigand affinitySplice variantsMain effectorAgonistAntagonist
PAC1-RPACAP27 = PACAP38 (Kd = 0.5 nmol/l) >VIP (Kd = 500 nmol/l)Short Very short Hip Hop1 Hop2 Hiphop1 Hiphop2 TM4AC, PLC, Ca2+ (TM4: L-type Ca2+ channel)Maxadilan (45)PACAP6-27 PACAP6-38 (42–44) M65 (46)
VPAC1-RPACAP = VIP (Kd = 1 nmol/l)AC, PLC, Ca2+VIP/GRF hybrid [Lys 15, Arg 16, Leu 27] VIP(1–7)-GRF(8–27)-NH2 (286 RO-25-1392 (48)Truncated VIP(3–7)-GRF(8–27)-NH2 (26)
VPAC2-RPACAP = VIP (Kd = 1 nmol/l)AC, Ca2+RO-25-1553 (47)PACAP(6–27) PACAP(6–39) (42–44)
  • TM, transmembraneous loop; GRF, growth hormone–releasing factor.