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目的 探讨胆碱能机制在 p H降低时颈动脉体 (CB)功能活动变化中的作用 .方法 在离体灌流条件下 ,记录颈动脉窦神经 (CSN)传入纤维的化学感受性单位放电 .结果 乙酰胆碱 (ACh)抑制单位放电 (n=16 ,P<0 .0 5 ) ,阿托品阻断 ACh的作用 ;尼古丁呈剂量依赖性增加单位放电 (n=10 ,r= 0 .94,P<0 .0 1) ;箭毒可阻断尼古丁的作用 ,对自发放电无显著影响 ;尼古丁并不增加化学感受性单位对 p H降低的放电反应 (n=19) ;p H降低时筒箭毒对化学感受性单位放电变化无显著影响 (n=17) ;硝苯吡啶 (5 mmol· L- 1 )对自发的基础单位放电 (n=8)和刺激诱导的电活动 (n=9)均无明显影响 .结论 胆碱能机制与 p H降低时 CB化学感受性功能活动的改变无直接关系
Objective To investigate the role of cholinergic mechanism in the changes of functional activity of carotid body (CB) during the decrease of p H.Methods The chemosensitive unit discharges of carotid sinus nerve (CSN) afferent fibers were recorded under extrinsic perfusion conditions.Results ACh inhibited unit discharge (n = 16, P <0. 05) and atropine blocked ACh. Nicotine increased unit discharge dose-dependently (n = 10, r = 0.94, P < However, nicotine did not increase the decrease of p H by chemoreceptors (n = 19). When p H decreased, the inhibitory effect of tuberculum lanceolata on chemosensitivity (N = 17). Nifedipine (5 mmol · L -1) had no significant effect on spontaneous basal unit discharge (n = 8) and stimulation-induced electrical activity (n = 9) Conclusion Cholinergic mechanism is not directly related to the change of CB chemokines activity when p H is decreased