Interaction of α- and β-Adrenergic Receptor Blocking Agents in the Conscious Rat

Abstract

In a commentary in this journal by Oates (2) on our work on interactions of α- and β-blockers (1), the author confirms our results; i.e. β-blockers (β2) block the α-blocker induced hypotension in conscious rats. However, this author was unable to reproduce the very strong antagonism that we found. This could maybe be due to strain differences in e.g. basal sympathetic tonus, role of α-receptors in maintenance of basal vasoconstriction, role of the adrenal medulla in sympathetic reflexes etc.

The point of the criticism (2) is however not only to what extent β-blockers might block α-blocker induced hypotension but, maybe more important, that our work gives the impression that unselective β-blockers completely prevent the hypotension caused by α-blockers. We agree that it would be unfortunate if our work gave an impression that a combination of α- and β-blockers would be inappropriate in clinical practise for this reason. We are eager, and happy to get the opportunity, to correct this impression.