Effect of unilateral carotid ligation on brainstem PNMT activity

Phenylethanolamine N-methyltransferase (PNMT) activity in the C1 and C2 regions of the brainstem was assayed in normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) with or without unilateral carotid artery ligation. PNMT activity was significantly higher in SHR than in WKY (P less than 0.01). PNMT activity in the C1 and C2 regions on non-ligated side in both WKY and SHR was significantly elevated compared with that on the ligated side. These results indicate that the activity of PNMT in adrenergic neurons may respond to baroreflex activation and that adrenergic neurons may be involved in blood pressure regulation.