【摘要】 用玻璃微电极记录了麻痹而清醒的家兔束旁核单位对腓总神经强电流刺激发生的痛敏放电,看到此放电可被已在 L₁—L₂水平切断的脊髓背半部外周端的电流刺激所抑制。在14个可被脊髓刺激明显抑制的痛敏单位中,此脊髓刺激效应在8个单位可因静脉注射酚妥拉明而阻断,其余6个单位则基本不受酚妥拉明注射的影响。进一步观察表明,在8个酚妥拉明有阻断作用的单位,其中7个单位在注射赛庚啶时不表现阻断作用;而在6个酚妥拉明不起阻断作用的单位,注射纳洛酮也不能阻断其脊髓刺激效应。由于我们在过去的工作中已经证明,凡是酚妥拉明有阻断作用的单位注射纳洛酮也都表现出阻断作用,而酚妥拉明无阻断作用的单位对注射赛庚啶却有阻断作用。因而本组实验结果支持我们已提出的推论,即在家兔脊髓背半部下行抑制通路中至少包含两类纤维,一类以内源性吗啡和去甲肾上腺素为递质或调制物,另一类以5-羟色胺为递质。更多还原

【Abstract】 Our previous experiments showed that nociceptive discharges of parafascicular（Pf）neuron elicited by strong electrical stimulation on peroneal nerve could bemarkedly inhibited by conditioning stimulation of the caudal stump of dorsal halfof spinal cord transected at L₁-L₂ level.We also found that the antinociceptiveaction of spinal stimulation could be blocked by phentolamine（Phl）in 16 of 27 Pfneurons while it was not effected in 11 remaining neurons by the same agent.In5 neurons,which had been influenced by.Ph 1,naloxone administration could also.block the effect of spinal stimulation.In 5 neurons,which had not been influencedby Phl,cyproheptadine administration could block the effect of spinal stimulationin 4.In present experiments we have shown that in 8 neurons influenced by Phl（0.2—0.5 mg/kg,iv.）cyproheptadine administration（1.0—3.0 mg/kg,iv.）can notblock the antinociceptive effect of spinal stimulation in 7 and that in 6 neurons,which have not been influenced by Phl,naloxone administration（1.0—1.2 mg/kg,iv.）,can not block the effect of spinal stimulation,either.All these results suggest that there may exist at least two groups of fibers descend-ing in the dorsal half of spinal cord to inhibit the transmission of nociceptive inputsat the spinal level:one is serotonergic and the other may use both noradrenalineand endogenous opioids in series as its neurotransmitters or modulators in the pro-priospinal circuits.更多还原