INFLUENCES ON THE GAMMA-MUSCLE SPINDLE SYSTEM FROM MUSCLE AFFERENTS STIMULATED BY KCL AND LACTIC-ACID
INFLUENCES ON THE GAMMA-MUSCLE SPINDLE SYSTEM FROM MUSCLE AFFERENTS STIMULATED BY KCL AND LACTIC-ACID
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DOI：
10.1016/0168-0102(93)90008-e
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发表时间：
1993-01-01
影响因子：
2.9
通讯作者：
SJOLANDER, P
中科院分区：
文献类型：
--
作者：
JOHANSSON, H;DJUPSJOBACKA, M;SJOLANDER, P
已知收缩代谢物在肌肉中的积累刺激III和IV组传入神经，并诱导γ-传出神经兴奋至同侧肌。本研究的目的是调查是否增加浓度的乳酸和氯化钾在一块肌肉可能会影响活动的初级和二级肌梭传入（MSA）从化学影响的肌肉和周围的肌肉。实验在7只用α-氯醛糖麻醉的猫上进行。同时记录2 - 8个来自小腿三头肌（GS）和后二头肌和半腱肌（PBSt）的单个MSA。的平均发射率和调制深度的MSA响应正弦拉伸的受体轴承肌肉进行了测定。记录了27个主要MSA（11个来自PBSt，16个来自GS）的响应。在这些明确的正弦反应的改变中，有24个是通过向GS肌肉的动脉供应中注射1 ml KCl（50 - 600 mM）或1 ml乳酸（20 - 200 mM）诱发的。此外，记录的所有继发性MSA（4例来自PBSt，1例来自GS）均显示对KCl和/或乳酸肌内浓度增加有相当大的影响。在原发性和继发性MSA，从GS以及从PBSt肌肉，几乎所有观察到的效果是兼容的静态梭运动神经元的激活。切断同侧L7-L6前根和麻醉GS神经后，对MSA的影响完全消失。静脉注射KCl和乳酸，以及动脉注射0.9%NaCl，在改变MSA反应无效。因此，浓度增加的收缩代谢物可能会激发初级和次级MSA从homeostomy和hetereostomy肌肉，最有可能通过梭运动反射引起的化学敏感的肌肉传入。
It is known that accumulation of contraction metabolites in muscles stimulates group III and IV afferents and induces excitation of gamma-efferents to the homonymous muscle. The aim of the present study was to investigate whether increased concentrations of lactic acid and KCl in one muscle may influence the activity in primary and secondary muscle spindle afferents (MSAs) from the chemically affected muscle and from surrounding muscles. The experiments were made on 7 cats anesthetized with alpha-chloralose. Recordings were made simultaneously from 2-8 single MSAs from the triceps surae (GS) and the posterior biceps and semitendinosus muscles (PBSt). The mean rate of firing and the depth of modulation of MSA responses to sinusoidal stretching of the receptor-bearing muscles were determined. Responses of 27 primary MSAs (11 from PBSt and 16 from GS) were recorded. On 24 of these clear-cut alterations in sinusoidal response were evoked by injection of 1 ml of KCl (50-600 mM) or 1 ml of lactic acid (20-200 mM) into the artery supply of the GS muscle. Also, all secondary MSAs recorded (4 from PBSt and 1 from GS) showed sizable effects to increased intramuscular concentrations of KCl and/or lactic acid. On both primary and secondary MSAs, from GS as well as from PBSt muscles, nearly all effects observed were compatible with activation of static fusimotor neurons. Effects on MSAs were completely abolished when the ipsilateral L7-L6 ventral roots were cut and when the GS nerve was anesthetized. Intravenous injections of KCl and lactic acid, as well as arterial injections of 0.9% NaCl, were ineffective in changing the MSA responses. Thus, increased concentrations of contraction metabolites may excite primary and secondary MSAs from both homonymous and heteronymous muscles, most probably via fusimotor reflexes elicited by chemosensitive muscle afferents.