Is ganglionic transmission through nicotinic receptors essential for the peristaltic reflex in the guinea-pig ileum?
Peristaltic reflex activity in the guinea-pig isolated ileum was elicited by slow intraluminal infusion of Tyrode solution. The reflex was abolished by the ganglionic blocking drug hexamethonium. However, in more than half of the preparations, the peristaltic reflex was restored by the opioid antagonist naloxone. Hexamethonium-resistant peristaltic waves were blocked by tetrodotoxin or atropine. These data suggest that ganglionic transmission through nicotinic acetylcholine receptors may not be essential for the peristaltic reflex provided that the inhibitory action of endogenous opioids has been eliminated.
D000818:Animals; D005724:Ganglia / Q000502:physiology*; D005730:Ganglionic Blockers / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006168:Guinea Pigs; D006584:Hexamethonium Compounds / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D009270:Naloxone / Q000494:pharmacology; D010528:Peristalsis / Q000187:drug effects*; D011978:Receptors, Nicotinic / Q000187:drug effects*; D012018:Reflex / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*
D005730:Ganglionic Blockers; D006584:Hexamethonium Compounds; D011978:Receptors, Nicotinic; D009270:Naloxone