...
首页> 外文期刊>The Journal of Physiology >Sympathetic modulation of muscle spindle afferent sensitivity to stretch in rabbit jaw closing muscles.
【24h】

Sympathetic modulation of muscle spindle afferent sensitivity to stretch in rabbit jaw closing muscles.

机译:肌肉纺锤体的交感神经调制对兔下颌闭合肌肉拉伸的敏感性。

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       

摘要

Previous reports showed that sympathetic stimulation affects the activity of muscle spindle afferents (MSAs). The aim of the present work is to study the characteristics of sympathetic modulation of MSA response to stretch: (i) on the dynamic and static components of the stretch response, and (ii) on group Ia and II MSAs to evaluate potentially different effects. In anaesthetised rabbits, the peripheral stump of the cervical sympathetic nerve (CSN) was stimulated at 10 impulses s(-1) for 45-90 s. The responses of single MSAs to trapezoidal displacement of the mandible were recorded from the mesencephalic trigeminal nucleus. The following characteristic parameters were determined from averaged trapezoidal responses: initial frequency (IF), peak frequency at the end of the ramp (PF), and static index (SI). From these, other parameters were derived: dynamic index (DI = PF - SI), dynamic difference (DD = PF - IF) and static difference (SD = SI - IF). The effects of CSN stimulation were also evaluated during changes in the state of intrafusal muscle fibre contraction induced by succinylcholine and curare. In a population of 124 MSAs, 106 units (85.4 %) were affected by sympathetic stimulation. In general, while changes in resting discharge varied among different units (Ia vs. II) and experimental conditions (curarised vs. non-curarised), ranging from enhancement to strong depression of firing, the amplitude of the response to muscle stretches consistently decreased. This was confirmed and detailed in a quantitative analysis performed on 49 muscle spindle afferents. In both the non-curarised (23 units) and curarised (26 units) condition, stimulation of the CSN reduced the response amplitude in terms of DD and SD, but hardly affected DI. The effects were equally present in both Ia and II units; they were shown to be independent from gamma drive and intrafusal muscle tone and not secondary to muscle hypoxia. Sympathetic action on the resting discharge (IF) was less consistent. In the non-curarised condition, IF decreased in most Ia units, while in II units decreases and increases occurred equally often. In the curarised condition, IF in group II units mostly increased. The results have important functional implications on the control of motor function in a state of 'high' sympathetic activity, like excessive stress, as well as in certain pathological conditions such as sympathetically maintained pain.
机译:以前的报道表明,交感神经刺激会影响肌肉纺锤传入(MSA)的活动。本工作的目的是研究MSA对伸展的反应的交感调节特性:(i)伸展反应的动态和静态成分,以及(ii)Ia和IIa组的MSA,以评估潜在的不同影响。在麻醉的兔子中,以10脉冲s(-1)刺激颈交感神经(CSN)的周围残端45-90 s。从中脑三叉神经核记录单个MSA对下颌骨梯形位移的响应。根据平均梯形响应确定以下特征参数:初始频率(IF),斜坡结束时的峰值频率(PF)和静态指数(SI)。从中得出其他参数:动态指数(DI = PF-SI),动态差(DD = PF-IF)和静态差(SD = SI-IF)。在由琥珀酰胆碱和咖喱诱导的肌内肌纤维收缩状态变化期间,还评估了CSN刺激的效果。在124个MSA人群中,有106个单位(占85.4%)受到交感神经刺激的影响。通常,虽然静息放电的变化在不同的单位(Ia vs. II)和实验条件(curarised vs. non-curarised)之间有所不同,从增强到强烈抑制射击,但对肌肉伸展的反应幅度却持续下降。这在对49个肌肉纺锤传入神经进行的定量分析中得到了证实和详细说明。在非治愈(23个单位)和治愈(26个单位)的情况下,刺激CSN都会降低DD和SD的响应幅度,但几乎不影响DI。在Ia和II单元中均存在相同的影响;它们被证明独立于伽马驱动和融合神经内肌张力,而不是继发于肌肉缺氧。对静息放电(IF)的交感作用不太一致。在非治愈状态下,大多数Ia单位的IF下降,而II单位的IF下降,并且上升的频率相同。在the愈的情况下,第二组的IF大部分增加。该结果对“高”交感神经活动状态下的运动功能控制具有重要的功能意义,例如过度的压力以及某些病理状态下,如交感神经维持性疼痛。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号