Effects of the Experimental Subarachnoid Hemorrhage on the Eicosanoid Receptors in Nicotine-induced Contraction of the Rat Basilar Artery

Background: Smoking is one of the most important risk factors for subarachnoid hemorrhage (SAH). The purpose of this study was to investigate the influence of experimental SAH and arachidonic acid metabolites on nicotine-induced contraction in the rat basilar artery. Methods: Rats were killed at 1 hour and 1 week after SAH, and the basilar artery was isolated and cut into a spiral strip. The effects of various eicosanoid receptor antagonists on nicotine-induced contraction in the rat basilar artery were investigated. Results: Antagonists of thromboxane A(2) (TXA(2)) and cysteinyl leukotriene (CysLT) receptors did not affect nicotine-induced contraction. In contrast, the antagonists of leukotriene B-4 (LTB4) receptors (BLT1 and BLT2) attenuated the nicotine-induced contraction in the rat basilar artery. We also observed that SAH did not influence the effect of TXA(2), LTB4, and CysLTs receptor antagonists on the nicotine-induced contraction. These results suggest that TXA(2) and CysLTs are not involved in nicotine-induced contraction, while LTB4 potentates this contraction in rat basilar artery. Conclusions: BLT2 receptor seemed to be more involved in the nicotine-induced contraction than the BLT1 receptor. SAH did not affect the involvement of eicosanoids in the nicotine-induced contraction of the rat basilar artery. The present study shows the involvement of some of the arachidonic acid metabolites into signaling pathways of nicotine-induced contraction. It will serve to improve therapeutic interventions of SAH and suggests a promising approach to protect the cerebral vasculature of cigarette smokers.