Effects of contraction and lactic acid on the discharge of group III muscle afferents in cats.
Effects of contraction and lactic acid on the discharge of group III muscle afferents in cats.
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收缩和乳酸对猫 III 组肌肉传入放电的影响。
DOI：
10.1152/jn.1993.69.4.1053
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发表时间：
1993
影响因子：
2.5
通讯作者：
Kaufman,MP
中科院分区：
文献类型：
--
作者：
Sinoway,LI;Hill,JM;Pickar,JG;Kaufman,MP
1.在巴比妥麻醉猫，我们研究了乳酸和静态收缩的相互作用，对第三组肌肉传入放电。只研究了感受野位于小腿三头肌的传入神经。2. 20个传入神经中的12个被60秒的静态收缩刺激。大部分的放电发生在收缩的最初几秒钟内。股动脉注射24 mM乳酸（1-4 ml），肌肉休息时刺激20个传入神经中的13个。在肌肉休息时重复注射乳酸导致快速耐受。然后在静态收缩的最后15秒期间注射乳酸（24 mM; 4 ml）。在8的9个传入的乳酸与肌肉在休息时，我们注意到恢复敏感性乳酸收缩。3.在单独的实验中，我们研究了二氯乙酸（DCA）对第III组肌肉传入静态收缩的反应的影响。DCA通过增加丙酮酸脱氢酶的活性形式的水平来减少乳酸的产生。4. DCA降低了静息和收缩时动脉和静脉乳酸浓度。DCA显着降低（31%; P < 0.05）传入纤维对收缩的反应。这种效应在收缩的前10 s内最为突出，并且不是由于DCA后机械刺激水平降低，因为在两次收缩期间峰值张力水平相同。（250字处删节）
1. In barbiturate-anesthetized cats we examined the interaction of lactic acid and static contraction on the discharge of group III muscle afferents. Only afferents whose receptive fields were located in the triceps surae muscles were studied. 2. Twelve of 20 afferents were stimulated by a 60-s static contraction. The majority of firing occurred within the first few seconds of contraction. Thirteen of 20 afferents were stimulated by femoral arterial injections of 24 mM lactic acid (1-4 ml) with the muscle at rest. Repeated injections of lactic acid with the muscle at rest led to tachyphylaxis. Lactic acid was then injected (24 mM; 4 ml) during the last 15 s of static contraction. In eight of nine afferents that were tachyphylactic to lactic acid with the muscle at rest, we noted a restored sensitivity to lactic acid during contraction. 3. In separate experiments we examined the effects of dichloroacetate (DCA) on the responses of group III muscle afferents to static contraction. DCA reduces the production of lactic acid by increasing levels of the active form of the enzyme pyruvate dehydrogenase. 4. DCA lowered arterial and venous lactate concentrations at rest and during contraction. DCA significantly decreased (31%; P < 0.05) the responses of the afferents to contraction. This effect was most prominent within the first 10 s of contraction and was not due to a reduced level of mechanical stimulation after DCA, because peak tension levels were the same during the two bouts of contraction.(ABSTRACT TRUNCATED AT 250 WORDS)