Biosynthesis of Substance P and Neurokinin A in the Enteric Nervous System
Immunocytochemical studies [1–3] have demonstrated that the guinea pig small intestine is supplied with a complex network of substance P-containing neurons. Extrinsic neurons project to the submucosal blood vessels and to the submucous ganglia. Intrinsic neurons in the submucous ganglia supply the villi and projections from the myenteric plexus supply most regions of the gut. Substance P-immunoreactive cell bodies are most numerous in the myenteric plexus. Recent studies have shown that extracts of guinea pig ileum contain neurokinin A and neuropeptide K  and these peptides have been identified in the same population of spinal ganglion cells and capsaicin-sensitive nerve fibres in the guinea pig ureter, inferior mesenteric. ganglion, heart and lung . Biosynthesis in vitro of substance P  and neurokinin A  has previously been demonstrated in rat dorsal root ganglia and experiments in vivo have shown de novo synthesis of substance P in the rat corpus striatum and its transport to the substantia nigra . This study extends this previous work to demonstrate in vitro biosynthesis of substance P, neurokinin A and neuropeptide K in enteric neurons of the myenteric plexus of the guinea pig ileum.
KeywordsMyenteric Plexus Capsaicin Sensitive Sensory Neuron Longitudinal Muscle Strip Submucous Ganglion Spinal Ganglion Cell
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