大鼠杏仁体基底外侧核中含D2受体的γ氨基丁酸神经元受多巴胺能末梢支配(英文)

杏仁体中的多巴胺(DA)和γ -氨基丁酸(GABA)递质系统均参与精神分裂症的病理过程,临床上一般用多巴胺II型受体(D2)阻断剂予以治疗。然而,目前尚不清楚GABA与D2受体是否共存,也不清楚DA能神经末梢与GABA能神经元之间的联系方式。本实验用共聚焦激光扫描显微镜(CLSM)和免疫电镜(IEM)研究了杏仁体关键性核团基底外侧核中GABA与D2受体的共存关系以及DA神经能末梢与GABA能神经元之间的突触关系。CLSM显示由谷氨酸脱羧酶(GAD)标记的GABA能神经元全部对D2受体呈免疫阳性反应,表明GABA能神经元含有D2受体。IEM显示,在 980个DA能神经末梢形成的突触中,45%的突触是由DA免疫反应阳性神经末梢直接(36% )或间接(9% )与GAD免疫反应阳性神经元的树突形成,另 55%是由DA免疫反应阳性神经末梢与未标记的神经元成分形成。DA GABA的直接性突触进而可区分为单突触 (16% )、汇聚突触 (14% )及轴 轴突触(6% )。而DA- GABA的间接性突触是个突触复合体。在该复合体中,DA免疫反应阳性末梢在一个未标记的末梢上形成对称性突触,而该未标记末梢又与GAD免疫反应阳性树突形成非对称性突触。在DA与未标记神经元成分之间的突触中,AD免疫反应阳性末梢分别与未标记胞体(4% )、树突(42% )及轴突末梢(9% )形成突触。所有DA突触无一例外均为?

γ-AMINOBUTYRIC ACID NEURONS BEARING D2 RECEPTORS ARE INNERVATED BY DOPAMINERGIC TERMINALS IN THE BASOLATERAL NUCLEUS OF RAT AMYGDALA

Although both dopamine (DA) and γ-aminobutyric acid (GABA) systems in the amygdala (AM) are involved in schizophrenia which is generally treated by administration of D2 receptor antagonists, it is not clear what is the collocation relationship between GABA and D2 receptors and what are the synaptic relationships between the dopaminergic terminals and GABAergic neurons in AM. Present study examined the coexistence of GABA and D2 receptors and synapses formed between dopaminergic terminals and GABAergic neurons in a key nucleus, the basolateral nucleus (BL), of rat AM by means of double labeling immunofluorescent confocal laser scanning microscopy (CLSM) and immunoelectron microscopy (IEM). CLSM revealed that the glutamic acid decarboxylase (GAD) immunolabeled GABAergic neurons were exclusively immunoreactive (IR) to D2 receptors. This indicates that all of the GABAergic interneurons bear D2receptors. IEM revealed that 45% of the DA synapses ( n = 980) were formed between the DA-IR terminals and GAD-IR neurons, and 55% of that formed between DA-IR terminals and unlabeled neuronal elements. In the DA-GABA synapses, the DA-IR terminals targeted either directly (36%) or indirectly (by serial synapse, 9% ) on GAD-IR dendritic structures. Furthermore, the direct DA-GABA synapses could be classified into single ( 16% ) , convergent ( 14% ) and axoaxonic (6%) types according to the number of synapses and the synaptic compositions. In the indirect case, the connection was a synaptic complex, in which a DA-IR terminal formed a synapse on another terminal that form the synapse on the GAD-IR dendrite. In the synapses of DA-unlabeled neuronal elements, the DA-IR terminals targeted on unlabeled perikarya (4%), dendrites (42%), and axons or terminals (9%). Interestingly, all of the DA synapses were exclusively symmetric. The present results suggest that D2 receptor antagonists might act on GABAergic neurons to weaken the DA neurotransmission in AM for clinical effects in schizophrenia. Beyond this, our data provide an anatomical basis for understanding the DA neural circuit in the BL of AM both in normal and schizophrenic conditions.