ALTERATION IN CANINE CARDIAC BASAL LEVELS OF CAMP AND CGMP, AND ELEVATED TISSUE PCO2 LEVELS, INDUCED BY CORONARY LIGATION

Forty dogs were subjected to coronary ligation by placing snares around the two consecutive diagonal branches of the left anterior descending coronary arteries. Both acute and chronic studies were made of intramyocardial gas tensions using the mass spectrometer. Other studies such as levels of cyclic nucleotides and myosin ATPase activity were made at the chronic periods. Following coronary ligation in dogs there was a significantly elevated tissue Pco2 level in the ischemic region and left ventricular border zone as late as 5 weeks post-ligation. There was a severe decrease in cAMP, whereas cGMP was either the same as normal values or in some cases significantly elevated, in the ischemic area during this post-ligation time. These data were reflected in the border area of the left ventricle, but to a lesser extent. There was a minor, but significant decrease in myosin enzymatic Vmax values in the border area of the left ventricle during the early post-ligation period when tissue Pco2 levels were significantly elevated. © 1978.