title: Effects of acetylcholine on the frequency-force relationship of the isolated dog atrium.
abstract: 1. The effects of acetylcholine on the frequency-force relationship in isolated atria of the dog were investigated in spontaneously beating and electrically paced preparations, which were suspended in a bath perfused with arterial blood from a carotid artery of a heparinized donor dog. 2. The developed tension at low frequencies of stimulation was less suppressed than at higher frequencies by an infusion of a relatively low dose level (1-2 microgram/min) of acetylcholine. At higher doses (4-10 microgram/min), acetylcholine suppressed the tension development at any given frequency.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D003864:Depression, Chemical; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects*; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*
chemical_list: D000109:Acetylcholine