MONOAMINES EFFECTS ON MOTONEURON DISCHARGE PATTERNS

描述(改编自申请人的摘要)： 这项提议的目标是检验单胺能输入的假设 保护脊髓运动神经元之间的正常阈值等级 一个游泳池。为了实现这一目标，对以下方面的影响进行调查 亚型特异性单胺类药物对运动神经元固有特性的影响 提出了突触输入的概念。利用去脑过氧化氢酶制剂 因为它既有下行单胺能束的补益活性，又有 正常的运动神经元招募。可逆性脊髓冷阻滞术 用于消除内源性单胺能活性。胞内单 电极电压钳(SEVC)方法提供运动神经元的测量 固有属性和突触输入。我们的目标是检验以下几点 具体假设：目标1：单胺类物质起到维持正常状态的作用 运动神经元的突触输入模式。目标2：单胺类物质产生 无失真运动神经元的平台电位和双稳态行为 正常的S与F的阈值差异。目标3：单胺类物质影响 S型神经元突触输入与固有属性的相互作用 和F运动神经元，通过允许突触输入产生平台电位 即使在胞体被电压钳制的情况下也是如此。这些研究已经 与脊髓损伤直接相关，其中紧张性单胺能丧失 输入可能会导致人类患者出现异常的运动流出。

DESCRIPTION (Adapted from applicant's abstract) : The goal of this proposal is to test the hypothesis that monoaminergic input acts to preserve the normal threshold hierarchy among spinal motoneurons in a pool. To achieve this goal, investigations of the effects of subtype-specific monoaminergic agents on motoneuron intrinsic properties and synaptic inputs are proposed. The decerebrate cat preparation is utilized because it has both tonic activity in descending monoaminergic tracts and normal motoneuron recruitment. Reversible cold block of the spinal cord is used to eliminate endogenous monoaminergic activity. Intracellular single electrode voltage clamp (SEVC) methods provide measurements of motoneuron intrinsic properties and synaptic inputs. Our aims test the following specific hypotheses: Aim 1: that monoamines act to preserve the normal pattern of synaptic input to motoneurons. Aim 2: that monoamines generate plateau potentials and bistable behaviors in motoneurons without distorting the normal S vs. F threshold differences. Aim 3: that monoamines influence the interaction between synaptic inputs and intrinsic properties of type S and F motoneurons by allowing synaptic inputs to generate plateau potentials in dendrites even when the soma is voltage clamped. These studies have direct relevance to spinal cord injury, where loss of tonic monoaminergic input may contribute to the abnormal motor outflow seen in human patients.