Abstract
To test the hypothesis that both coronary autoregulation and metabolic vasodilation can be mediated by the same substance, we have analysed measured autoregulation curves with the aid of a simple mass balance model. In an open-chest dog preparation, increasing the heart rate by pacing results in a nearly parallel shift of the autoregulation curve to a higher flow (Q) level. We assume a unique relationship between vascular conductance and interstitial concentration of a vasodilating substance [A]. Applying a compartmental mass balance, it is possible to predict with a minimum of assumptions the increase of flow between two points with increased production but having the same vasodilator concentration. The simple result of this analysis is: delta Q = delta production/[A]. If the vasodilator concentration varies by more than a factor 2 between low and high conductance points, the autoregulation curve cannot shift in a parallel fashion as a result of an increased production rate, but rather will become less and less steep. We conclude that a single vasodilator cannot be responsible for both autoregulation and metabolic vasodilation unless complex assumptions are made, for which there is as yet no experimental support
Original language | English |
---|---|
Pages (from-to) | 354-358 |
Journal | Basic Research in Cardiology |
Volume | 76 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1981 |