Heckman C J
Veterans Administration, Chicago, IL.
Med Sci Sports Exerc. 1994 Dec;26(12):1480-90.
An acute animal model (dorsal hemisection of the spinal cord in the decerebrate cat preparation) has been developed that closely mimics the spasticity in humans that occurs subsequent to partial spinal cord injury and hemiparetic stroke. In this animal model, there are severe disruptions in the pattern of recruitment and rate modulation of motoneurons. The cellular mechanisms of these deficits are being studied with a combined experimental/computer simulation approach. The initial studies indicate that changes in the intrinsic properties of motoneurons are not important, which means the mechanism for changes in recruitment and rate patterns must reside in an alteration in the organization of the synaptic input to motoneurons. Computer simulation studies of the effects of different synaptic inputs on motoneuron outputs show that inhibitory inputs can, under certain conditions, generate substantial disruptions in recruitment and rate modulation. Recent data indicate that the monoamines noradrenalin and serotonin, which are released by fiber tracts originating in the brainstem, may play an important role in maintaining normal levels of inhibition in spinal circuits. Pharmacological interventions based on the monoamines may provide effective means of reducing the deficits in recruitment and rate modulation.
已经建立了一种急性动物模型（在去大脑猫制备中进行脊髓背侧半横切），该模型紧密模拟了人类在部分脊髓损伤和偏瘫性中风后出现的痉挛。在这个动物模型中，运动神经元的募集模式和频率调制存在严重紊乱。正在通过实验与计算机模拟相结合的方法研究这些缺陷的细胞机制。初步研究表明，运动神经元内在特性的变化并不重要，这意味着募集和频率模式变化的机制必定存在于运动神经元突触输入组织的改变中。对不同突触输入对运动神经元输出影响的计算机模拟研究表明，在某些条件下，抑制性输入可在募集和频率调制方面产生重大紊乱。最近的数据表明，源自脑干的纤维束释放的单胺类物质去甲肾上腺素和5-羟色胺，可能在维持脊髓回路正常抑制水平方面发挥重要作用。基于单胺类物质的药物干预可能提供减少募集和频率调制缺陷的有效手段。
