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 A2 (TXA2) and cysteinyl leukotriene (CysLT) receptors did not affect nicotine-induced contraction. In contrast, the antagonists of leukotriene B4 (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 TXA2, LTB4, and CysLTs receptor antagonists on the nicotine-induced contraction. These results suggest that TXA2 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.
Division of Pharmacology, Radioisotope Research Center, Kyoto University, Kyoto, Japan. Electronic address: jixuchjp@yahoo.co.jp.
Xu
X
Ji
Cristina C
CC
Trandafir
Aimin
A
Wang
Kazuyoshi
K
Kurahashi
D000818:Animals; D001488:Basilar Artery / Q000187:drug effects*; D005260:Female; D066298:In Vitro Techniques; D020024:Leukotriene Antagonists / Q000494:pharmacology; D007975:Leukotriene B4 / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018055:Receptors, Eicosanoid / Q000187:drug effects / Q000502:physiology*; D044244:Receptors, Thromboxane A2, Prostaglandin H2 / Q000819:agonists; D013345:Subarachnoid Hemorrhage / Q000378:metabolism* / Q000503:physiopathology
D020024:Leukotriene Antagonists; D018722:Nicotinic Agonists; D018055:Receptors, Eicosanoid; D044244:Receptors, Thromboxane A2, Prostaglandin H2; D007975:Leukotriene B4; D009538:Nicotine