title: Influence of myocardial isomyosins on cardiac performance and oxygen consumption.
abstract: There was 21% isomyosin V1 in the 12 month SHR (Spontaneous Hypertensive Rat) and 70% isomyosin V1 in the 6 month WKY (Wystar-Kyoto), nevertheless there was no difference in maximum developed pressure nor maximum dP/dt in the isovolumically beating hearts of the two sets of animals. [Hearts were perfused with hypercalcemic perfusate in the presence of isoproterenol (10(-7)M)]. There was, however, a a 32% reduction in oxygen consumption per gram of dry weight per beat in the 12 month SHR as compared to the 6 mo WKY. Associated with a shift towards isomyosins V2 and V3 in the 6 and 12 month WKY and SHR there was no corresponding change in maximum dP/dt nor developed pressure, but there was a conservation in oxygen consumption.
mesh_terms: D000375:Aging; D000818:Animals; D001794:Blood Pressure; D002118:Calcium / Q000494:pharmacology; D006321:Heart / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D007527:Isoenzymes / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D010101:Oxygen Consumption; D051381:Rats; D011918:Rats, Inbred SHR; D011920:Rats, Inbred WF
chemical_list: D007527:Isoenzymes; D009218:Myosins; D002118:Calcium