Abellán M T, Adell A, Honrubia M A, Mengod G, Artigas F
Department of Neurochemistry, Instituto de Investigaciones Biomédicas de Barcelona, CSIC (IDIBAPS).
Neuroreport. 2000 Apr 7;11(5):941-5. doi: 10.1097/00001756-200004070-00009.
The activation of GABAB receptors hyperpolarizes 5-HT neurons and reduces cell firing. In situ hybridization showed the presence of the GABAB-RI receptor transcript in virtually all 5-HT neurons of the dorsal and median raphe nuclei (DR and MnR, respectively) whereas the GAD transcript was present mainly outside these nuclei. The systemic administration of baclofen increased the in vivo 5-HT release in the DR, MnR and several projection areas. As shown previously in the DR, the application of baclofen in the MnR increased the local 5-HT output. Thus, although 5-HT neurons contain inhibitory GABAB-RI receptors, baclofen increased 5-HT release in some brain areas, likely by a preferential action on terminal GABAB autoreceptors in inhibitory inputs to 5-HT neurons. The scarcity of GAD-expressing cells in the DR and MnR suggests that these inputs originate mainly outside these nuclei.
GABAB受体的激活使5-羟色胺（5-HT）能神经元超极化并减少细胞放电。原位杂交显示，在背侧中缝核和中缝正中核（分别为DR和MnR）几乎所有的5-HT能神经元中均存在GABAB-RI受体转录本，而谷氨酸脱羧酶（GAD）转录本主要存在于这些核团之外。巴氯芬的全身给药增加了DR、MnR及几个投射区域的体内5-HT释放。如先前在DR中所示，在MnR中应用巴氯芬增加了局部5-HT输出。因此，尽管5-HT能神经元含有抑制性GABAB-RI受体，但巴氯芬在某些脑区增加了5-HT释放，这可能是通过对5-HT能神经元抑制性输入中的终末GABAB自身受体的优先作用实现的。DR和MnR中表达GAD的细胞稀少，表明这些输入主要起源于这些核团之外。
