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目的探讨中枢胆碱能M_1受体在应激条件下对颈动脉窦压力感受器反射(CSR)的影响。方法健康雄性SD大鼠随机分成非应激组(n=12)和应激组(n=12),后者接受不可逃避的足底电击,每日2次,每次持续2h。应激1周的SD大鼠,经筛选、麻醉后孤离双侧颈动脉窦区,将不同窦内压(ISP)与其对应的平均动脉压(MAP)值进行Logistic曲线拟合,求得ISP-MAP、ISP-增益(Gain)关系曲线及其特征参数,观察侧脑室微量注射选择性胆碱能M_1受体拮抗剂哌仑西平(PRZ)对CSR的影响。结果侧脑室注射PRZ(1.0 mmol/L,5μl)导致应激大鼠ISP-MAP关系曲线后半程明显下移(P<0.05),ISP-Gain关系曲线中部明显上移(P<0.05),反射参数中饱和压和最大增益时的窦内压值减少(P<0.05),而反射最大Gain加大(P<0.05);侧脑室注射相同剂量、容积的PRZ对非应激大鼠CSR的各项指标均无明显影响(P>0.05);侧脑室注射PRZ不能使应激的CSR水平恢复到非应激水平(P<0.05)。结论中枢胆碱能M_1受体参与应激对CSR功能抑制性重调定;除此之外,应激调节中尚有其他神经机制因素的参与。
Objective To investigate the effect of central cholinergic M_1 receptor on carotid sinus baroreceptor reflex (CSR) under stress conditions. Methods Healthy male Sprague-Dawley rats were randomly divided into non-stress group (n = 12) and stress group (n = 12). The latter received an unavoidable plantar shock twice a day for 2 hours. After 1-week stress, SD rats were screened and anesthetized, and bilateral carotid sinusoids were isolated. Logistic curve fitting was performed between different sinus pressure (ISP) and corresponding mean arterial pressure (MAP) -MAP, ISP-Gain curve and its characteristic parameters to observe the effects of microinjection of parenteral cholinergic Pirenzepine (PRZ) into the lateral ventricle on CSR. Results The intracerebroventricular injection of PRZ (1.0 mmol / L, 5 μl) resulted in significant down-regulation of ISP-MAP (P <0.05) and up-regulation of ISP- The sinusoidal pressure at saturation pressure and maximum gain in the reflex parameters decreased (P <0.05), while the maximal reflection increased (P <0.05). The intracerebroventricular injection of the same dose and volume of PRZ had no significant effect on CSR There was no significant difference between each index (P> 0.05). The intracerebroventricular administration of PRZ failed to restore the stress CSR level to non-stress level (P <0.05). Conclusion The central cholinergic M_1 receptor is involved in repression of CSR inhibition by stress. In addition, there are other neuropathological factors involved in stress regulation.