OPIATE ANALGESIA: THE LAMINA I STT PROJECTION

阐明吗啡和其他阿片类药物的基本作用机制 生产止痛药可以促进更具特异性的止痛药的发展 治疗，但阿片类药物对中枢伤害性感受器的生理影响 底物尚未建立。虽然人们普遍认为 阿片类药物抑制脊髓背角神经元对伤害性刺激的反应 刺激物，很少有研究真正研究它们对上升的影响， 伤害性感觉神经元。特别是，几乎没有观察到 在构成脊髓丘脑束(STT)神经元的I层神经元上 这条经典的痛觉通路大约有一半。伤害性的概念-- 特异型和热感型I层STT神经元是一个整体 疼痛和体温的中央代表成分表明 阿片类药物对这一途径的影响及其主要影响的假说 丘脑内侧核(Sm)的终末可能是必需的。 作为镇痛剂有效性的基础行动。因此，本研究 定量检查全身和局部给药的影响 吗啡对伤害性和热感受性反应特性的影响 I板层STT细胞(以及不投射到丘脑的I板层细胞) 以及麻醉猫sm内伤害性神经元的表达。这个 对生理上不同的选择行为的鉴定 I板层STT神经元的亚群将表明进一步的分析 对该系统的研究有助于完善鞘内镇痛技术。 对Sm中直接阿片类药物作用的鉴定将支持 这可能是脊椎上止痛作用的主要部位， 因此，对最终的发展至关重要 非成瘾和非精神活性中枢止痛疗法。

Elucidation of the basic mechanisms by which morphine and other opiates produce analgesia could advance the development of more specific analgesic therapies, yet the physiological effects of opiates on central nociceptive substrates have not been established. While it is generally believed that opiates suppress the responses of spinal dorsal horn neurons to noxious stimuli, few studies have actually examined their effects on ascending, nociceptive-specific neurons. In particular, almost no observations have been made on lamina I spinothalamic tract (STT) neurons, which compose about half of this classical pain pathway. The concept that nociceptive- specific and thermoreceptive-specific lamina I STT neurons are an integral component of the central representation of pain and temperature suggests the hypothesis that opiate effects on this pathway, and on its major terminus in the medial thalamus, nucleus submedius (Sm), may be essential actions underlying their effectiveness as analgesics. Thus, this research examines quantitatively the effects of systemic and locally administered morphine on the response characteristics of nociceptive and thermoreceptive lamina I STT cells (and lamina I cells that do not project to the thalamus) and of nociceptive-specific neurons in sm in the anesthetized cat. The identification of selective actions on physiologically distinct subpopulations of lamina I STT neurons will suggest that further analysis of this system could help refine the technique of intrathecal analgesia. The identification of direct opiate effects in Sm will support the possibility that this is a primary site of supraspinal analgesic action, and therefore, of fundamental importance for the eventual development of non-addictive and non-psychoactive central analgesic therapies.