Effect of moxonidine on carotid sinus baroreflex in anesthetized rats.

Abstract

Aim: To study the effect of moxonidine (Mox) on carotid sinus baroreflex.

Methods: By perfusing the carotid sinus in anesthetized rats, the functional parameters of baroreflex were measured. The femoral artery was perfused with constant flow and the change of perfusing pressure was recorded to determine the effect of Mox on vascular tone.

Results: Mox 32 and 100 mumol.L-1 shifted the functional curve of carotid sinus baroreflex to the right and upward, with the reduction in peak slope and in reflex decrease of mean arterial pressure, suggesting that Mox produced an inhibitory effect on baroreflex. The effect of Mox 100 mumol.L-1 on baroreflex was completely blocked by efaroxan 100 mumol.L-1. Mox increased vascular resistance.

Conclusion: Mox inhibits carotid baroreflex via its constrictive action on sinus wall.