Bombesin, gastrin releasing peptide and vasoactive intestinal peptide excite myenteric neurons.

Intracellular recording methods were used to study the actions of bombesin, gastrin releasing peptide and vasoactive intestinal peptide on electrical behavior of AH/Type 2 myenteric neurons in guinea-pig ileum in vitro. Each peptide evoked membrane depolarization associated with increased input resistance, enhanced excitability and suppression of hyperpolarizing after-potentials. The effects of the peptides simulated slow synaptic excitation in the myenteric plexus and are consistent with a neurotransmitter or neuromodulatory function.