Effects of sympathectomy on endothelin-1 and histamine responses of rabbit carotid artery.

1. The effects of chronic sympathectomy on contractile responses of rabbit common carotid artery was studied in vitro. 2. Endothelin-1 (ET-1), histamine, KC1 and papaverine concentration-response curves of sympathectomized and sham-operated (control) vessels were recorded and analyzed. Effects of endothelium removal also were investigated. 3. The contractions elicited by ET-1 and histamine in sympathectomized preparations did not change when compared with controls. Papaverine, which produces endothelium-independent relaxation, and KC1, which produces endothelium-independent contraction, did not differ from controls. No significant difference was observed between the contractile responses of sympathectomized vessels and those of control vessels to ET-1 and histamine after the removal of endothelium. 4. These results indicate that chronic sympathectomy did not affect the sensitivity to exogenous ET-1 and histamine of the vascular smooth muscle.