Recent views on integrated coronary control: significance of non-uniform regional control of coronary flow conductance.
1. Previous work from this laboratory and others has shown that powerful autonomic influences modulate coronary flow. In particular, the parasympathetic nervous system produces vasodilatation when activated by baroreceptors via the vagus nerve. 2. Differences exist in baroreflex coronary vasodilator mechanisms among the right, circumflex and anterior descending coronary vascular beds in the awake chronically instrumented dog. 3. Our hypothesis is that neurogenic acetylcholine acting from the adventitial side and endothelial nitric oxide from the luminal aspect of coronary smooth muscle compete with powerful intrinsic myogenic constrictor mechanisms to regulate regional flow conductance. 4. There is also increasing evidence that heterogeneity of control systems exists in different-sized coronary vessels within an individual coronary vascular bed. 5. It is concluded that coronary vessels in vascular beds can no longer be assumed to respond in a uniform manner to neural, myogenic, metabolic or humoral factors. 6. These new perspectives of regional control mechanisms have important implications for understanding pathophysiological mechanisms inducing and sustaining tachyarrhythmias involved in ischaemic heart disease.
Quail
A W
AW
Discipline of Human Physiology and Neuroscience Group, Faculty of Medicine and Health Sciences, University of Newcastle, Callaghan, New South Wales, Australia. hpawq@mail.newcastle.edu.au
Cottee
D B
DB
Porges
W L
WL
White
S W
SW
D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D017704:Baroreflex; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000033:anatomy & histology / Q000294:innervation / Q000378:metabolism; D004285:Dogs; D006439:Hemodynamics; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000033:anatomy & histology / Q000294:innervation / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000502:physiology; D052250:Nitric Oxide Synthase Type III; D014655:Vascular Resistance
C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D000109:Acetylcholine