We recently reported that the acute, systemic administration of conjugated equine estrogen (CEE) significantly attenuated the ventricular arrhythmias of ischemia and reperfusion. In estrogen-treated dogs, this attenuation of reperfusion arrhythmias was preceded by a significantly higher coronary perfusion pressure during ischemia (31±2mmHg vs. 18±4mmHg in non-treated dogs). The purpose of the current investigation was to determine the effect of graded doses of CEE (5, 10, and 20ug) on the coronary vasculature of the anesthetized, instrumented beagle (n=6). At 5-10 minutes after administration of CEE, we observed a modest but significant vasodilation which occurred most consistently at the lOug dose. Coronary blood flow increased from 82±20ml/min/100gms to 112±27ml/min/100gms (p<0.05). Frequently, the vasodilation was followed by an abrupt return to baseline flow. There even appeared to be signs of subsequent coronary vasoconstriction, but this could not be confirmed statistically. We then isolated coronary perfusion pressure changes in response to these graded doses of CEE by maintaining coronary blood flow at baseline levels with a peristalsic perfusion pump. Coronary perfusion pressure decreased after CEE administration, suggesting vasodilation. In conclusion, CEE appears to affect basal vascular tone which may cause a significant increase in perfusion to an ischemic vascular bed.
|Original language||English (US)|
|State||Published - 1996|
All Science Journal Classification (ASJC) codes
- Molecular Biology