Kamei J, Aoki T, Hitosugi H, Iwamoto Y, Kasuya Y
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
Jpn J Pharmacol. 1992 Oct;60(2):133-40. doi: 10.1254/jjp.60.133.
The influence of diabetes on the effects of morphine on the responses of ventrobasal (VB) thalamic neurons to mechanical noxious stimuli were studied in chloral hydrate-anesthetized rats. Animals were rendered diabetic by an injection of streptozotocin (60 mg/kg, i.v.). Morphine (0.3 mg/kg), administered i.v., produced a reduction in the responsiveness of VB thalamic neurons to noxious stimulation in control rats. This effect was reversed by naloxone. In contrast, the inhibitory effects of morphine on the nociceptive responses of VB thalamic neurons were significantly attenuated in diabetic rats, as compared with the controls. However, there were no significant differences in inhibitory potency between diabetic and control rats when morphine (30 nM) was administered intrathecally. It seems likely that these changes in the sensitivity of VB thalamic neurons to morphine are, to some extent, the source of the reduction in the analgesic efficacy of morphine in diabetic rats.
在水合氯醛麻醉的大鼠中，研究了糖尿病对吗啡作用于腹后外侧（VB）丘脑神经元对机械性伤害性刺激反应的影响。通过静脉注射链脲佐菌素（60mg/kg）使动物患糖尿病。静脉注射吗啡（0.3mg/kg）可使对照大鼠中VB丘脑神经元对伤害性刺激的反应性降低。这种作用可被纳洛酮逆转。相比之下，与对照大鼠相比，吗啡对糖尿病大鼠VB丘脑神经元伤害性反应的抑制作用明显减弱。然而，当鞘内注射吗啡（30nM）时，糖尿病大鼠和对照大鼠之间的抑制效力没有显著差异。VB丘脑神经元对吗啡敏感性的这些变化似乎在某种程度上是糖尿病大鼠中吗啡镇痛效果降低的原因。
