【摘要】 在无麻醉的麻痹猫,以伤害性电刺激内脏大神经传入纤维诱发的连续内脏躯体反射放电为指标,分别刺激腓总神经、延髓中缝大核区以及包括导水管周围灰质、中央中核在内的脑区以产生相应的抑制效应。分别全身与脊髓硬膜内给予纳洛酮以及对氯苯丙胺与羟甲丙基甲基麦角酰胺(Methysergide),观察各种抑制效应的变化。发现:(1)静脉注射纳洛酮虽在不少的动物上能暂时地逆转上述效应,但逆转的程度都是不完全的,硬膜内给药也有类似作用;(2)静脉或腹腔内注射对氯苯丙胺一般能较完全而持久地阻断这些抑制效应,但对腓总神经的抑制效应影响较小,硬膜内给药也有相似的效果;(3)羟甲丙基甲基麦角酰胺(静脉或硬膜内注射)主要阻断腓总神经的抑制效应,对中缝大核的抑制效应影响较小。上述结果显示,阿片肽能和5-羟色胺能下行系统均直接参与内脏痛觉传递的延髓中缝-脊髓调节机制,但后者所起的作用可能更大。更多还原

【Abstract】 Experiments were designed to compare the differential roles played by theserotonergic and opioid peptidergic descending systems which originated in thenucleus raphe magnus(Rm)and nucleus reticularis magnocellularis(Rmc)inthe control of transmission of visceral nociceptive imputs at spinal level.The viscero-somatic reflexes(VSR)elicited by nociceptive stimulation of thesplanchnic nerve were recorded in the unanesthetized,immobilized Cats.Inorder to elicit an inhibitory effect on the VSR,several brain regions such as Rm,Rmc,the periaqueductal grey,the nucleus centrum medianum as well as the com-mon peroneal nerve(PN)were stimulated with proper intensity.The inhibitoryeffects were evaluated after administration of antagonists of opioid peptides andserotonin.It was found that intravenous or intrathecal administration of naloxone couldtemporarily and partially reverse the PN inhibitory effect(PNI)in most cases andbrain stimulation-produced inhibition(mostly in Rm, RmI)in a limited numberof cats.The RmI reversals were dose-dependent.However,systemic injection of p-chloroamphetamine could permanentlyand markedly block the inhibitory effects in a large majority of cats.Intrathecalinjections had similar results.Intravenous or intrathecal administration of me-thysergide had predominant blocking effect on PNI but less effect on RmI.These findings indicate that both the serotonergic and the opioid peptidergicraphe-spinal descending systems may participate in the modulation of the informa-tion of visceral pain at the spinal level.However,the serotontergic one appearsto be more prominent.更多还原