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David E Euler, Sympathetic influences on the native canine coronary collateral circulation, Cardiovascular Research, Volume 29, Issue 1, January 1995, Pages 33–37, https://doi.org/10.1016/S0008-6363(96)88543-9
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Abstract
Objective: The aim was to investigate the influence of the sympathetic nervous system on the native collateral circulation in the intact heart. Methods: Experiments were performed on 10 open chest dogs anaesthetised with α chloralose. The left anterior descending coronary artery was cannulated and embolised with 25 μm microspheres. Collateral resistance was determined from measurements of aortic pressure and retrograde flow. Additional haemodynamic measurements included left ventricular pressure and blood flow in the circumflex coronary artery. Results: Coronary embolisation decreased retrograde resistance from 41.5(SEM 6.0) to 20.1(1.9) mm Hg·ml−1·min−1 (P < 0.01). Left stellate stimulation for 60 s (10 Hz) significantly increased circumflex blood flow and decreased circumflex resistance from 2.1(0.3) to 1.6(0.2) mm Hg·ml−1·min−1. Retrograde resistance during sympathetic stimulation decreased from 19.7(1.8) to 16.8(1.8) mm Hg·ml−1·min−1. (P < 0.01). Transient occlusion of descending aorta resulted in changes in perfusion pressure and retrograde flow that were similar to those observed during stellate stimulation. Stellate stimulation after β blockade with timolol (0.1 mg·kg−1) increased circumflex resistance from 1.9(0.2) to 2.3(0.3) mm Hg·ml−1·min−1 (P < 0.01) but did not alter retrograde resistance. Conclusions: The sympathetic nervous system does not have a direct effect on native coronary collateral vessels. Increased sympathetic input to the heart does not result in a coronary steal phenomenon. The primary determinant of flow and resistance in the native collateral network during sympathetic activation is the arterial perfusion pressure.
