Tetrodotoxin sensitivity of high K+-induced 86Rb efflux in the duodenal circular muscle of pigs.
The 86Rb efflux by high K+ was measured simultaneously during the mechanical responses in pig duodenal circular muscle using a superfusion technique. A slightly higher K+ (17.7-23.6 mM) simultaneously induced tetrodotoxin (TTX)-sensitive relaxation and 86Rb efflux. Much higher K+ (47.2-143.4 mM) contracted and also increased the 86Rb efflux markedly, but the extent of TTX-sensitive efflux remained the same as the one at 17.7-23.6 mM K+, indicating that the TTX-insensitive efflux was contraction-related. The former efflux may lead to hyperpolarization linked to relaxation.
Kondoh
T
T
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Kimura
I
I
Kimura
M
M
D000818:Animals; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology*; D012413:Rubidium / Q000493:pharmacokinetics*; D012844:Sincalide / Q000494:pharmacology; D013552:Swine; D013779:Tetrodotoxin / Q000494:pharmacology*
D013779:Tetrodotoxin; D012844:Sincalide; D012413:Rubidium; D011188:Potassium