title: [Relationship between the rate of myocardial contraction and relaxation under the effect of neural and humoral factors].
abstract: The speed ratio of contractions and relaxations was studied on an isolated canine heart perfused via a donor dog under haemodynamic conditions closely resembling the natural ones, the stimulation being achieved by irritation of the sympathetic and vagal nerves, and by administration of adrenalin, noradrenalin, or acetylcholine. The contraction and relaxation speeds were determined by the first derivative of the left ventricular pressure curve. All the used types of nervous and humoral stimulation were seen to cause synchronous changes in these speeds, uniform in their direction, and closely correlating, which suggests the existence of a certain mechanism of autoregulation that maintains definite proportions of the myocardium contraction and relaxation speeds.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D004558:Electric Stimulation; D004837:Epinephrine / Q000494:pharmacology; D006321:Heart / Q000294:innervation / Q000502:physiology*; D006339:Heart Rate; D009200:Myocardial Contraction; D009638:Norepinephrine / Q000494:pharmacology; D013268:Stimulation, Chemical; D013564:Sympathetic Nervous System / Q000187:drug effects; D014630:Vagus Nerve / Q000187:drug effects
chemical_list: D000109:Acetylcholine; D009638:Norepinephrine; D004837:Epinephrine
vernacular_title: Vzaimootnoshenie skorosteĭ sokrashcheniia i rasslableniia miokarda v usloviiakh nervnykh i gumoral'nykh vliianiĭ