Taglietti V, Pietra P, Zucca G
J Physiol (Paris). 1976 Jan;70(6):795-812.
Dilute solutions of Barium Chloride have been tested on frog's isolated muscle spindles with the aim of clarifying the processes leading to the afferent discharge. In the presence of Ba++ the spindle properties are modified as follows: 1. The discharge of slack spindles increases and becomes extremely regular. 2. The phasic response to stretching is enhanced, the tonic responses being on the contrary virtually suppressed. Under Ba-treatment therefore the spindle changes from a phasic-tonic receptor to a merely phasic receptor. 3. The "silent period" following every propagated spike is prolonged while the safety margin of the "abortive" into propagated spike conversion becomes maximal under Ba-treatment. Additionally, this analysis showed that, when a "true" action potential arises in the spindle, it propagates not only to the stem fibre, but also to all the sensory endings in the spindle intracapsular network. Comparison between the effects of Ba++ and those produced by TEA and ouabain indicates that the action of Ba++ on muscle spindles results from conjunction of two factors : a) reduction of K permeability, and b) enhanced efficiency of an electrogenic Na/K-pump in spindle nerve membranes.
已对蛙的离体肌梭进行了氯化钡稀溶液测试，目的是阐明导致传入放电的过程。在存在Ba++的情况下，肌梭特性发生如下改变：1. 松弛肌梭的放电增加并变得极其规律。2. 对拉伸的相位反应增强，相反，紧张性反应实际上受到抑制。因此，在Ba处理下，肌梭从相位 - 紧张性感受器转变为仅相位感受器。3. 每次传播性峰电位后的“静息期”延长，而在Ba处理下，“顿挫性”转变为传播性峰电位转换的安全边际达到最大。此外，该分析表明，当肌梭中出现“真正的”动作电位时，它不仅传播到主干纤维，还传播到肌梭囊内网络中的所有感觉末梢。Ba++的作用与TEA和哇巴因产生的作用之间的比较表明，Ba++对肌梭的作用是由两个因素共同作用的结果：a）钾通透性降低，b）肌梭神经膜中电生性钠/钾泵效率提高。
