Contractile effects of manganese on taenia of guinea pig cecum.
The present study was undertaken to examine Mn as a contractile agent in its own right in the absence of extracellular Ca and after the depletion of Ca from agonist-releasable stores. The results show that isolated strips of taenia coli depolarized by high-K, Ca-free solution will contract when Mn is present. Similarly, carbachol will evoke contractions in tissues incubated in Ca-free, Mn-containing solutions. In addition, it seems possible to stimulate contraction by releasing Mn from an agonist-releasable intracellular store in the absence of extracellular Ca and Mn. Therefore the possibility exists that cations employed as Ca antagonists may in fact support contraction.
Lategan
T W
TW
Department of Pharmacology, Oxford University, United Kingdom.
Brading
A F
AF
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D002432:Cecum / Q000502:physiology*; D003106:Colon / Q000502:physiology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008345:Manganese / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000502:physiology
D008345:Manganese; D002217:Carbachol; D002118:Calcium