CHRONIC MORPHINE--REGULATION OF ION CONDUCTANCES

本提案中的实验旨在揭示自适应 长期阿片类药物治疗引起的神经元活动变化。 从行为上可以观察到， 对吗啡的依赖随着长期使用而发展。 奇怪的是， 在细胞和生物化学水平上，耐受程度和 依赖性要小几个数量级 的差距 观察可能表明，有多种机制安排， 这一系列的行为可以解释 宽容 另一种可能性是调节离子电导 除了那些直接受阿片类药物影响的人外， 治疗，他们可能占增加的耐受性水平， 依赖 阿片类药物激活钾通道和/或非活性钙 干扰细胞兴奋性和功能的通道。 的继续存在的 阿片类药物的存在，耐受性发展到这些直接行动， 阿片类药物。 此外，细胞中还有其他适应性变化， 与特定离子无直接关系的功能和兴奋性 由阿片类药物控制的通道 对这些渠道的监管 阿片类药物的“间接”门控是这项提案的主题。 来自该位点神经元的细胞内和全细胞记录 三叉神经脊束核蓝斑和胶状质 将被制成脑切片 有了这两种制剂， 将研究两种阿片介导的反应， 钾传导与谷氨酸的突触前抑制 release. 在长期阿片类药物治疗中观察到一个一致的结果 是cAMP的基础和刺激水平的增加。 在这 建议，cAMP依赖性过程对递质的影响 释放和离子电导由电压、变送器和G门控， 蛋白质将被鉴定和表征。 这些依赖cAMP的 将在急性应用（分钟或小时）后研究过程 阿片类激动剂和长期（天）用 吗啡 通过研究离子调节的改变， 电导不直接受阿片类药物的影响，它可能是可能的， 阐明了高水平的耐受性的机制， 产生行为水平。

The experiments in this proposal are aimed at uncovering adaptive changes in neuronal activity that result from chronic opioid treatment. Behaviorally it can be observed that a high degree of tolerance to and dependence on morphine develops with chronic use. It is curious that, at the cellular and biochemical level, the degree of tolerance and dependence is orders of magnitude smaller. The disparity in the observations may suggest that there are multiple mechanisms arranged in series that could account for the high level of behavioral tolerance. Another possibility is that regulation of ion conductances other than those directly affected by opioids are altered with chronic treatment and they may account for the increased level of tolerance and dependence. Opioids activate potassium channels and/or the inactive calcium channels to perturb cell excitability and function. In the continued presence of opioids, tolerance develops to these direct actions of opioids. There are, in addition, other adaptive changes in cell function and excitability not directly related to the specific ion channels gated by opioids. The regulation of those channels 'indirectly' gated by opioids is the subject of this proposal. Intracellular and whole cell recordings from neurons in the locus coeruleus and substantia gelatinosa of the spinal trigeminal nucleus will be made in brain slice preparations. With these two preparations, two opioid mediated responses will be investigated, the increase in potassium conductance and the presynaptic inhibition of glutamate release. One consistent observation made with chronic opioid treatment is an increase in the basal and stimulated level of cAMP. In this proposal, the effects of cAMP-dependent processes on transmitter release and ion conductances gated by voltage, transmitters and G- proteins will be identified and characterized. These cAMP-dependent processes will be studied after acute application (min or hours) of opioid agonists and in animals treated chronically (days) with morphine. By investigating the alteration in the regulation of ion conductances not directly affected by opioids, it may be possible to clarify the mechanisms by which the high levels of tolerance found at the behavioral level are generated.