Zarrindast M R, Sabetkasai M
Department of Pharmacology, School of Medicine, University of Tehran, Iran.
Arch Int Pharmacodyn Ther. 1992 Jul-Aug;318:5-12.
The antinociceptive effects of GABAergic agents in presence or absence of swim-stress were investigated in mice, using the tail-flick test. Swim-stress, the GABAB agonist baclofen and the GABAA agonist muscimol raised the threshold of withdrawal reactions to nociceptive stimulation. The antinociception, induced by an interaction of stress and GABA agonists, was higher than that of stress or a GABA agonist alone. The GABAB antagonist phaclofen and the GABAA antagonists bicuculline and picrotoxin decreased the antinociceptive action induced by stress plus baclofen. Picrotoxin administration also decreased the response of baclofen. Picrotoxin and biculline, but not phaclofen, reduced the antinociceptive response induced by muscimol in stressed mice. Administration of picrotoxin, bicuculline or phaclofen alone did not decrease the stress-induced antinociception. The antagonists even increased the base line latencies in both normal and stressed mice. It is concluded that stimulation of both GABAA and GABAB receptor sites has an antinociceptive effect, but that the involvement of a GABAergic mechanism in stress-induced antinociception is unlikely.
采用甩尾试验，在小鼠中研究了γ-氨基丁酸（GABA）能药物在有无游泳应激情况下的抗伤害感受作用。游泳应激、GABAB激动剂巴氯芬和GABAA激动剂蝇蕈醇均提高了对伤害性刺激的撤反应阈值。应激与GABA激动剂相互作用诱导的抗伤害感受高于单独应激或GABA激动剂诱导的抗伤害感受。GABAB拮抗剂巴氯芬、GABAA拮抗剂荷包牡丹碱和印防己毒素降低了应激加巴氯芬诱导的抗伤害感受作用。给予印防己毒素也降低了巴氯芬的反应。印防己毒素和荷包牡丹碱，但不是巴氯芬，降低了应激小鼠中蝇蕈醇诱导的抗伤害感受反应。单独给予印防己毒素、荷包牡丹碱或巴氯芬不会降低应激诱导的抗伤害感受。拮抗剂甚至增加了正常和应激小鼠的基线潜伏期。得出的结论是，刺激GABAA和GABAB受体位点均具有抗伤害感受作用，但GABA能机制不太可能参与应激诱导的抗伤害感受。
