溴苄铵或6 - 羟基多巴胺抗性，小鼠输精管曲张中动作电位诱发的Ca2+瞬变。
Bretylium or 6-OHDA-resistant, action potential-evoked Ca2+ transients in varicosities of the mouse vas deferens.
作者信息
Jackson V Margaret, Cunnane Tom C
机构信息
University Department of Pharmacology, Mansfield Road, Oxford, OX1 3QT, UK.
出版信息
Br J Pharmacol. 2002 Apr;135(8):1845-50. doi: 10.1038/sj.bjp.0704677.
Action potential-evoked calcium transients in varicosities in mouse vas deferens were monitored using laser scanning confocal microscopy. Their significance was examined by comparison with excitatory junction potentials (EJPs) and neurogenic contractions, both indirect measurements of transmitter release. Bretylium abolished EJPs, as well as the ATP and NA-mediated phases of contraction. However, bretylium revealed a prominent late component of contraction that was atropine-sensitive. Bretylium abolished calcium transients in 21%, enhanced in 16% and had no effect in 63% of varicosities examined. Pre-treatment with 6-OHDA reduced NA levels to below detectable levels but many strings of varicosities still responded to nerve impulses with 'normal' calcium transients. Varicosities in which calcium transients were abolished by these agents were sympathetic. The identity of those varicosities in which calcium transients were resistant to bretylium (sympathetic but no uptake-1 sites, parasympathetic, sensory) remains to be established.
使用激光扫描共聚焦显微镜监测小鼠输精管曲张部位动作电位诱发的钙瞬变。通过与兴奋性接头电位（EJP）和神经源性收缩进行比较来检验它们的意义，这两者都是递质释放的间接测量指标。溴苄铵消除了EJP以及ATP和去甲肾上腺素（NA）介导的收缩期。然而，溴苄铵揭示了一个突出的晚期收缩成分，该成分对阿托品敏感。在检查的曲张部位中，溴苄铵消除了21%的钙瞬变，增强了16%，对63%没有影响。用6-羟基多巴胺（6-OHDA）预处理可将NA水平降低至可检测水平以下，但许多串状曲张部位仍对神经冲动产生“正常”的钙瞬变反应。被这些药物消除钙瞬变的曲张部位是交感神经的。那些钙瞬变对溴苄铵有抗性的曲张部位（交感神经但无摄取-1位点、副交感神经、感觉神经）的身份仍有待确定。
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