Inhibitory action of atrial natriuretic factor on cholinergic and nonadrenergic, noncholinergic neurotransmission in guinea pig small intestine.
We studied the effect of synthetic rat atrial natriuretic factor (ANF) (Ser 99-Tyr 126) on the isolated guinea pig proximal ileum. This preparation contained about one-third of the endogenous tissue ANF content which, for the most part, comes from the blood. ANF inhibited, in a dose-dependent manner, cholinergic twitch contractions (EC50 = 4.2 nM), nonadrenergic, noncholinergic (NANC) primary and rebound contractions and histamine-induced sustained tonic contraction (but not carbachol induced contraction) of the longitudinal muscle. Ascending enteric reflex (AER) contractions of the circular muscle were inhibited though not dose-dependently. We suggest pre- and post-synaptic actions of sustained intestinal tissue and blood ANF levels which may play a role in regulating motor activity and muscle tone of the small intestine.
Matusak
O
O
Clinical Research Institute of Montreal, Quebec, Canada.
Kuchel
O
O
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002217:Carbachol / Q000494:pharmacology*; D004558:Electric Stimulation; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D012018:Reflex; D009435:Synaptic Transmission / Q000187:drug effects
D006632:Histamine; D009320:Atrial Natriuretic Factor; D002217:Carbachol