The peristaltic reflex: An analysis of the nerve pathways and their pharmacology

摘要: The enteric reflexes in isolated segments of the distal colon and rectum guinea-pig were studied by applying localized distensions recording consequent changes circular muscle activity, tension during propulsion a bolus vitro. Lesions wall made to locate nerve pathways involved pharmacological tests applied investigate natures transmitters released types receptors involved. Distension produced transient contraction on oral side sustained relaxation anal side. Both nerve-mediated. They elicited deprived mucosa submucosa. Interruption Auerbach's plexus, but not interruption submucosal prevented their conduction. ascending excitatory reflex was partly blocked hyoscine also methysergide or making preparation tachyphylactic action 5-hydroxytryptamine. apparently involve neurons releasing 5-HT-like transmitter as well cholinergic neurons. descending inhibitory antagonized hyoscine, guanethidine, mepyramine. It is assumed that activated this are identical with non-cholinergic, non-adrenergic, found throughout intestine. If both acted simultaneously same area muscle, response tended dominate. Pellets faeces, covered thin layer resin, introduced into ends colon. propelled analwards at speeds 0.5-1.6 mm/s. Tension records showed pellets preceded followed ring contraction. methysergide. Descending waves observed empty These occurred spontaneously initiated stretch. did occur presence tetrodotoxin. postulated three factors may contribute colon: which evoke contractions above bolus; cause relaxations below; which, once set up travel an direction.