Vasomotor coronary oscillations: A model to evaluate autoregulation
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A simple model was proposed to characterise the oscillatory and nonoscillatory pattern of canine coronary circulation responses induced by a small dose of a vasodilator adenosine or the Ca2+-channel blocker diltiazem. This model consists of two differential equations describing the interaction of dilating (D) and constricting (C) resistance components. With the assumption that the rate constants associated with (D) were dependent on adenosine concentration and those associated with (C) were a function of Ca2+ channels, the model predicted: a) a damped oscillation of resistance to flow at low dose of adenosine, b) a predominant vasodilation at high dose of adenosine, and c) a sustained vasodilation in response to diltiazem. Parameters characterising the coronary resistance were evaluated by fitting the model results to calculated resistance from measured coronary flow and aortic pressure. As well, the model predicted accurately the peak resistance to great cardiac and coronary sinus venous flow in patients. This study indicates that the oscillation frequency of coronary resistance induced by a low dose of adenosine (0.01 mg/kg) is indicative of the uptake rate of adenosine by the heart and the coronary resistance provides considerable information on vasomotor control of the coronary circulation.
Key wordsadenosine coronaryresistance oscillations vasomotion
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- 6.Editorial (1988) Yin and yang in vasomotor control. Lancet 2:19–21Google Scholar
- 11.Harrison DG, Freiman PC, Armstrong ML, Marcus ML, Heistad DD (1987) Alterations of vascular reactivity in atherosclerosis. Circ Res 61 (Suppl.II):II 74–80Google Scholar
- 14.Kenner T, Ono K (1988) Oscillations of arterial blood flow. Proc the 9th Int Conf Cardiovasc Syst Dynamics Soc, pp 109–112Google Scholar
- 15.Klassen GA, Armour JA (1990) Adenosine-induced oscillations in coronary flow: a probe to evaluate vasomotor control. Coronary Art Dis 1:221–232Google Scholar
- 16.Lansman JB, Hallam TJ, Rink TJ (1987) Single stretch-activated ion channels in endothelial cells as mechanotransducers. Nature 325:811–813Google Scholar
- 18.Marzilli M, Klassen GA, Marraccini P, Camici P, Trivella MG, L'Abbate A (1988) Effects of adenosine on coronary blood flow in conscious man. Proc the 9th Int Conf Cardiovasc Syst Dynamics Soc 343–346Google Scholar
- 19.Marzilli M, Klassen GA, Marraccini P, Camici P, Trivella MG, L'Abbate A (1989) Coronary effects of adenosine in conscious man. Eur Heart J 10 (Suppl F):78–81Google Scholar
- 21.Nees S, DesRosiers C, Bock M (1987) Adenosine receptors at the coronary endothelium: functional implication. In: Gerlach E, Becker BF (eds) Topics and perspectives in adenosine research. Springer-Verlag, Berlin, pp 454–467Google Scholar
- 23.Sacher G (1942) Periodic phenomena in the interaction of two neurons. Bull Math Biophy 4:77–81Google Scholar
- 26.van Breeman V, Saida K (1989) Cellular mechanisms regulating [Ca2+]i of smooth muscle. Ann Rev Physiol 51:315–329Google Scholar