Spasmogenic effects of L-ascorbic acid on the guinea pig isolated ileum preparation.
The mechanism of actions of L-ascorbic acid (AA) on the guinea pig isolated ileum wasstudied. AA (neutralized, 10(-3) M) produced a stimulated motility (A effect) and a potentiation in acetylcholine (ACh)-induced contraction (B effect). The A effect showed a tachyphylaxis, and was inhibited by tetrodotoxin, atropine, adenosine, morphine, strychnine, Mg2+, papaverine and glucose- and Ca2+-free medium, but was stimulated by eserine. Thus, AA appears to have not only a direct myogenic effect but also a neurogenic effect by stimulating ACh release from intramural cholinergic nerves.
D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000502:physiology; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D010208:Papaverine / Q000494:pharmacology; D010830:Physostigmine / Q000494:pharmacology; D013331:Strychnine / Q000494:pharmacology
D009020:Morphine; D001285:Atropine; D010830:Physostigmine; D010208:Papaverine; D013331:Strychnine; D008274:Magnesium; D005947:Glucose; D000241:Adenosine; D001205:Ascorbic Acid; D002118:Calcium