Gastric and pyloric motor response to sympathetic nerve stimulation after chemical sympathectomy.

This study evaluated the effect of electrical stimulation of the greater splanchnic nerve on gastric and gastroduodenal motility in 6-hydroxydopamine (6-OHDA)-pretreated anesthetized dogs. Biopsies from the stomach, pylorus and duodenum were obtained and analyzed by catecholamine fluorescence microscopy. Degeneration of adrenergic terminals in Auerbach's plexus was complete at 1 week. The majority of stimulations in control dogs or dogs treated with 6--OHDA produced contractions in the gastric body, antrum, and pylorus and relaxation of inhibition in the duodenum. The excitatory motor responses in the gastric body, antrum and pylorus were unaffected by the administration of hexamethonium. Following atropine administration, contractions due to splanchnic nerve stimulation virtually were abolished in the antrum, pylorus and duodenum and were reduced in number in the gastric body. Relaxation and inhibition were no longer observed in the duodenum after atropine. The greater splanchnic nerve appears to contain both excitatory are inhibitory cholinergic pathways to the musculature of the stomach, pylorus, and duodenum.