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Neuropeptide Y inhibits excitatory enteric neurons supplying the circular muscle of the guinea pig small intestine

1987; Elsevier BV; Volume: 92; Issue: 6 Linguagem: Inglês

10.1016/0016-5085(87)90628-7

1528-0012

Peter Holzer, Irmgard Th. Lippe, L. Barthó, Alois Saria,

Child Nutrition and Feeding Issues

The effect of neuropeptide Y on the motor activity of the circular and longitudinal muscle of the guinea pig small intestine was investigated. Neuropeptide Y (0.3-30 nM) inhibited, in a concentration-dependent manner, the ascending enteric reflex contraction of the circular muscle; both the cholinergic and noncholinergic component of the ascending enteric reflex were suppressed. Neuropeptide Y also blocked nerve-mediated phasic contractions of the circular muscle, induced by dimethylphenylpiperazinium or ceruletide, and abolished the peristaltic movements of the small intestine. Nerve-mediated cholinergic and noncholinergic contractions of the longitudinal muscle, induced by electrical field stimulation, were only slightly depressed by neuropeptide Y. Further analysis showed that neuropeptide Y did not act directly on intestinal muscle but interrupted excitatory pathways of the enteric nervous system. The effect of neuropeptide Y did not involve activation of alpha-adrenoceptors, opioid receptors, or P1 purinoceptors or the release of endogenous factors stimulating these receptors. These findings suggest a possible physiologic role of neuropeptide Y as a nonnoradrenergic inhibitory transmitter involved in the enteric nervous control of intestinal circular muscle activity.