[Mechanogram profile of the guinea pig intestine. The supertone].
The authors detected the possibility, during the phase of low tone contraction of isolated intestine, to develop a further contraction, a supertone (S), simply washing the preparation. It has been evidenced that S appears when the tonic phase is low; it does not disappear if the tone is increased lowering NaCl concentration in the saline plasma; is absent in the KCl induced contraction; is induced also by low doses of atropine; is decreased by digitalic agents. The results obtained lead the authors to conclude that: the reduced tonic phase is due to a positive factor, the Ca++ of the cytoplasm, and to a negative factor, the high level of cytoplasmic Na+. This high level of Na+ is maintained by a dynamic equilibrium with ion input through channels opened by muscarinic agent and output by a Na-K-ATP asi pump. The Na+ output is predominant and fraction of Ca++, no longer counterbalanced by Na+, causes the rise of S.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D006168:Guinea Pigs; D007422:Intestines / Q000502:physiology*; D009119:Muscle Contraction / Q000187:drug effects; D011189:Potassium Chloride / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology
D012965:Sodium Chloride; D011189:Potassium Chloride; D001285:Atropine; D002118:Calcium
Profilo del meccanogramma di intestino di cavia. Il sopratono.