VPAC2 Receptor Activation Mediates VIP Enhancement of Population Spikes in the CA1 Area of the Hippocampus

Abstract: The receptors mediating vasoactive intestinal polypeptide (VIP) enhancement of synaptic transmission to pyramidal cell bodies were investigated. RO 25–1553 (VPAC 2 agonist) mimicked the excitatory effect of VIP on population spike (PS) amplitude. [K 15 , R 16 , L 27 ] VIP (1–7)/GRF (8–27) (VPAC 1 agonist) caused only a small increase in PS amplitude. The effect of VPAC 2 agonist (but not of the VPAC 1 agonist) persisted upon blockade of GABAergic transmission and was strongly attenuated upon inhibition of PKA. In conclusion, VPAC 2 receptor activation mediates VIP enhancement of PS amplitude in the hippocampus essentially through a PKA‐dependent mechanism.