β3肾上腺素能受体对大鼠胸主动脉平滑肌舒缩活动的影响及其机制  

Effects of β_3 adrenoceptors on the contractility of rat thoracic aorta smooth muscle and the mechanism

作　　者：李晓鹏[1] 赵倩倩[1] 杨岚[1] 李海清[1] 崔香丽[1] 

机构地区：[1]山西医科大学生理学系,省部共建细胞生理学重点实验室,太原030001

出　　处：《中国应用生理学杂志》2016年第1期69-73,共5页Chinese Journal of Applied Physiology

基　　金：山西省自然科学基金(2012011040-8);山西医科大学科技创新基金([2012]11号)

摘　　要：目的:观察激动β_3-肾上腺素能受体(β_3-AR)对大鼠胸主动脉平滑肌舒缩活动的影响及其可能机制。方法:30 mmol/L高钾生理盐溶液预收缩去内皮大鼠离体胸主动脉后,观察β_3肾上腺素能受体激动剂BRL37344(BRL)对主动脉舒缩活动的影响。用SR59230A(SR)、普萘洛尔(Pra)、L-NNA、H-89以及Iberiotoxin(IBTX)预孵主动脉平滑肌,探讨其可能存在的作用机制;应用免疫组织化学法,观察β_3-AR在大鼠胸主动脉的分布。结果:1BRL对预收缩的去内皮大鼠胸主动脉产生显著的舒张作用,舒张百分比为(10.59±0.79)%;2大鼠胸主动脉组织切片中可以观察到β_3-AR在内皮和平滑肌层都有表达;3给予Pra后,BRL对血管的舒张百分比无显著性变化;SR能明显拮抗BRL的血管舒张作用;4用L-NNA阻断NOS或者H-89抑制PKA后,BRL对血管的舒张作用有不同程度的减弱;5 IBTX阻断大电导钙依赖性钾通道后,BRL对血管的舒张作用减小。结论:激动β_3-AR产生血管舒张作用,平滑肌β_3-AR的作用与NOS以及PKA信号转导途径有关,是通过影响大电导Ca^(2+)依赖性钾通道(BK通道)来实现的。Objective： To observe the effect of β3 adrenoceptors （β3-AR） activation on rat thoracic aorta smooth muscle contractility and the possible related mechanism. Methods： The endothelium removed thoracic aorta was pre-contracted with 30 mmoL/L KCl physiological saline solution （PSS）. Then the tension of the thoracic aorta was recorded in presence of BRL37344 （BRL） to determine the action of β3-AR. The tension of the thoracic aorta was also recorded in the presence of Propranolol （PRA）, SR59230A （SR）, L-NNA, H-89 and Iberiotoxin （IBTX） respectively to reveal the underling mechanism of β3-AR activation on rat vascular smooth muscle. Immunohistochemistry was adopted to confirm the existence and the distribution of β3-AR in rat thoracic aorta. Results： The results showed that： ①The thoracic aorta was relaxed by β3-AR activation, with a relaxation percentage of （ 10.59 ± 0.79）. ②β3-AR was expressed in both endothelial and smooth muscle layer in thoracic aorta sections of rats. ③ PRA did not block the effect of BRL on the thoracic aorta. The relaxation actions of BRL could be antagonized by pre-incubating the thoracic aorta with SR. ④ L-NNA （a NOS inhibitor） and H-89 （a PKA inhibitor） reversed the relaxation effect of BRL on vascular smooth muscle. ⑤The effect of BRL was decreased after application of Ibriotoxin （IBTX）, a large conductance calcium dependent potassium channel blocker. Conclusion： The results confirmed that activation of β3-AR led to relaxation of thoracic aorta smooth muscle. The relaxation action of β3-AR on smooth muscle of rat thoracic aorta was related to activation of NOS and PKA signaling pathway. Large conductance Ca^2＋ -K^＋ channels were involved in the relaxation action of β3-AR activation on rat thoracic aorta smooth muscle.

关 键 词：大鼠 Β3肾上腺素能受体 主动脉 平滑肌 NOS PKA Ibriotoxin 

分 类 号：R331.3[医药卫生—人体生理学]