Scatton B, Serrano A
Naunyn Schmiedebergs Arch Pharmacol. 1986 Apr;332(4):380-3. doi: 10.1007/BF00500091.
Previous studies have suggested that GABA exerts an indirect facilitatory influence on cerebral noradrenergic transmission that is likely to be mediated via GABA-ergic synapses involved in polysynaptic neuronal circuits controlling noradrenergic cell activity. In order to confirm these findings, we have studied the effect of GABA mimetics on extracellular DOPAC in the locus coeruleus (a reliable index of noradrenergic neuronal activity) of the rat through the use of in vivo voltammetry with carbon fibre electrodes. Systemic administration of progabide, its active metabolite SL 75.102, of depamide or muscimol increased the height of the DOPAC oxidation peak in the locus coeruleus; the effect of muscimol was antagonized by co-administration of bicuculline. Intra-locus coeruleus infusion of even a high concentration of muscimol (1 microgram) failed to alter extracellular DOPAC in this area. These results add further weight to the view that GABA exerts a facilitatory influence on noradrenergic neurons (via an increase in their cell firing) which is not effected at the level of their cell bodies or in the surrounding region.
先前的研究表明，γ-氨基丁酸（GABA）对脑内去甲肾上腺素能传递产生间接的促进作用，这种作用可能是通过参与控制去甲肾上腺素能细胞活动的多突触神经元回路中的GABA能突触介导的。为了证实这些发现，我们通过使用碳纤维电极进行体内伏安法，研究了GABA模拟物对大鼠蓝斑（去甲肾上腺素能神经元活动的可靠指标）细胞外3,4-二羟基苯乙酸（DOPAC）的影响。全身给予普罗加比、其活性代谢物SL 75.102、地帕明或蝇蕈醇可增加蓝斑中DOPAC氧化峰的高度；同时给予荷包牡丹碱可拮抗蝇蕈醇的作用。即使在蓝斑内注入高浓度（1微克）的蝇蕈醇，也未能改变该区域的细胞外DOPAC。这些结果进一步支持了以下观点：GABA对去甲肾上腺素能神经元产生促进作用（通过增加其细胞放电），而这种作用并非在其细胞体水平或周围区域产生。
