Effects of glyceryl trinitrate on functionally regressed newly developed collateral vessels in conscious dogs.
The effects of glyceryl trinitrate on collateral blood flow and regional myocardial function during a 2 min coronary occlusion were evaluated in 10 conscious dogs with well developed collateral vessels. Collateral growth was promoted by brief, repeated, reversible coronary occlusions. After partial regression in collateral function a small dose of glyceryl trinitrate (5 micrograms.kg-1) was injected intravenously 1 min before coronary occlusion. After pretreatment with glyceryl trinitrate the collateral blood flow velocity (mean[SD]) increased from 3.0(0.9) to 4.4(1.4) cm.s-1 (p less than 0.05). After 2 min of occlusion the percentage systolic subendocardial segment shortening in the collateral dependent zone increased from 7.8(6.1) to 12.6(6.7)% (p less than 0.05). The blood flow debt repayment after release of the occlusion decreased from 122(41) to 68(34%) (p less than 0.05). Thus in conscious dogs with regressed newly developed collaterals a major component of the beneficial effects of glyceryl trinitrate on collateral circulation is dilatation of collateral vessels, as evidenced by a pronounced increase in collateral blood flow and myocardial function during a transient period of coronary occlusion.
Fujita
M
M
Dalton Research Center, University of Missouri-Columbia.
McKown
D P
DP
McKown
M D
MD
Franklin
D
D
D000818:Animals; D003097:Collateral Circulation / Q000187:drug effects*; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000503:physiopathology*; D003331:Coronary Vessels / Q000187:drug effects*; D004285:Dogs; D006321:Heart / Q000503:physiopathology; D006439:Hemodynamics; D005996:Nitroglycerin / Q000494:pharmacology*
D005996:Nitroglycerin