RT Journal Article
SR Electronic
T1 INITIATION OF AUTOMATICITY BY ACETYLCHOLINE AND NOREPINEPHRINE IN ISOLATED QUIESCENT ATRIA OF THE CAT
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 303
OP 311
VO 148
IS 3
A1 Gerald E. Groblewski
A1 Victor DiStefano
YR 1965
UL http://jpet.aspetjournals.org/content/148/3/303.abstract
AB Rates and durations of spontaneous beating of isolated cat atria are the same in Chenoweth-Koelle solution and in Tyrode solution at 29°C. In Chenoweth-Koelle solution the spontaneous rate at 37°C is two times that at 29°C and the duration of beating at 37°C is one half that at 29°C. Rates of beating induced by acetylcholine in isolated quiescent cat atria in Chenoweth-Koelle solution and in Tyrode solution at 29°C are the same; rates induced by norepinephrine in Chenoweth-Koelle solution and in Tyrode solution at 29°C are the same. However, the rates induced by norepinephrine are two times those induced by acetyichohine. The suppression of the ability of acetylcholine to start quiescent cat atria in Chenoweth-Koelle solution was abolished in Tyrode solution and proved to be K+ ion dependent. Differences in the actions of acetyicholine and norepinephrine in starting isolated cat atria suggest that different mechanisms of action are involved. The Williams & Wilkins Comapny