5-HT1A, SST1, and SST2 receptors mediate inhibitory postsynaptic potentials in the submucous plexus of the guinea pig ileum

Abstract

Vasoactive intestinal peptide (VIP) immunoreactive neurons are important secretomotor neurons in the submucous plexus. They are the only submucosal neurons to receive inhibitory inputs and exhibit both noradrenergic and nonadrenergic inhibitory synaptic potentials (IPSPs). The former are mediated by α2-adrenoceptors, but the receptors mediating the latter have not been identified. We used standard intracellular recording, RTPCR, and confocal microscopy to test whether 5-HT1A, SST1, and/or SST2 receptors mediate nonadrenergic IPSPs in VIP submucosal neurons in guinea pig ileum in vitro. The specific 5-HT1A receptor antagonist WAY 100135 (1 μM) reduced the amplitude of IPSPs, an effect that pe..