Vasorelaxant effects of calcium channel blockers on isolated thoracic aortic rings from thyroxine-induced hypertensive rats
- VernacularTitle:钙通道阻滞剂对甲亢性高血压大鼠胸主动脉舒张反应的影响
- Author:
Songnan JIN
;
Jingyu JIN
;
Yanyou SU
;
Jinfu WEN
- Publication Type:Journal Article
- Keywords:
T-type calcium channels;
L-type calcium channels;
hyperthyroidism;
hypertension;
thoracic aorta;
relaxation
- From:
Chinese Pharmacological Bulletin
2009;25(12):1615-1618
- CountryChina
- Language:Chinese
-
Abstract:
Aim To investigate the effects of T-and L-type calcium channel blockers on isolated thoracic aorta from thyroxine-induced hypertensive rats.Methods Hyperthyroidism was induced by administering L-thyroxine (T4,0.5 mg·kg~(-1),sc) daily for 16 days.Sham-treated euthyroid control rats were only received vehicle saline for 16 days. Experiments were performed in isolated thoracic aorta rings from euthyroid and hyperthyroid rats. Mibefradil and diltiazem were used to inhibit T-and L-type calcium channels,respectively.Results Thyroid hormone excess for 16 days induced characteristic changes in body weight,heart rate and systolic blood pressure in rats. The body weight was significantly decreased,heart rate and systolic blood pressure were increased in T4-treated rats. Thoracic aorta morphology was altered in T4-treated rats. The thickness of adventitia was increased with hypertrophy and hyperplasia of the smooth musle cells in T4-treated rats. Vasorelaxant effect of T-and L-type calcium channel blockers were accentuated in aortic rings from T4-treated rats.Conclusion These data suggest that T-and L-type calcium channels are functionally upregulated in isolated thoracic aorta from hyperthyroid rats and they,may be a therapeutic target in thyroxine-induced hypertension.
