氨基甙类抗生素对家兔离体颈动脉窦压力感受器放电的抑制作用

Inhibitory effect of aminoglycoside antibiotics on rabbit carotid baroreceptor activity in vitro

实验用自制的压力感受器标本灌流 记录一体化装置 ,研究氨基甙类抗生素、胞外钙离子浓度变化和L 型钙通道拮抗剂对家兔离体颈动脉窦压力感受器活动 (CS BRA)的影响。研究中发现 ,(1)链霉素 (0 2 5～ 0 75mmol/L)和庆大霉素 (0 43～ 1 2 9mmol/L)浓度依赖性地抑制CS BRA ,停药后可基本恢复 ;(2 )高钙灌流液 (3 3mmol/L)抑制CS BRA ,而微量钙灌流液 (10 -5mol/L数量级 )兴奋CS BRA ;(3)维拉帕米和地尔硫在选择性阻断L 型钙通道的有效浓度范围内 (<10 -7mol/L)对CS BRA没有显著影响 ,在更高浓度 (>10 -6mol/L)时 ,则抑制CS BRA。结果表明 :(1)氨基甙类抗生素特异性地抑制CS BRA ,是一种新的研究压力感受器活动的工具药 ;(2 )钙离子不是形成压力感受器发生器电位的主要离子 ,而且L 型钙通道在CS BRA中没有显著作用 ;(3)氨基甙类抗生素对CS BRA的抑制作用可能不是通过阻断L

The present study was to investigate the effects of aminoglycoside antibiotics, changes in extracellular Ca 2+ concentration and antagonists of L type Ca channels on the activity of rabbit carotid sinus baroreceptors (CS BRA) in isolated and superperfused carotid sinus carotid sinus nerve (CS CNS) preparations, using extracellular recording technique. The results are as follows. (1) Streptomycin (0 25～0 75 mmol/L) and gentamycin (0 43～1 29 mmol/L) inhibited CS BRA in a dose dependent manner, which recovered after the drugs were washed out. (2) Perfusion with high Ca 2+ (3 3 mmol/L) solution inhibited CS BRA, while perfusate with trace Ca 2+ (in the order of 10 -5 mol/L) increased it. (3) Verapamil and diltiazem had no effect on CS BRA at a concentration of 10 -7 mol/L, but inhibited it at higher concentrations (>10 -6 mol/L). These results suggest: (1) aminoglycoside antibiotics can inhibit CS BRA specifically, thus providing a new tool for the study of baroreceptors; (2) calcium ions are not necessary for producing generator potentials of baroreceptors, and the L type calcium channel does not seem to be involved in CS BRA per se ; and (3) the inhibitory effects of aminoglycoside antibiotics on CS BRA may not be related to the blocking of L type calcium channels.[WT5HZ]