Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology. Via Bonanno, 6. 56126 Pisa, Italy.
Curr Top Med Chem. 2012;12(4):254-69. doi: 10.2174/1568026799078787.
Anxiety disorders have been linked to alterations in γ-aminobutyric acid (GABA) neurotransmission. GABA interacts with the ligand-gated ion channels, GABAA receptor (GABAA-R) subtypes, and regulates the flow of chloride into the cell, causing neuron hyperpolarization. GABAA-Rs are assembled from a family of 19 homologous subunit gene products and form mostly hetero-oligomeric pentamers. The major isoforms of the GABAA-Rs contain α, β and γ subunits and show a regional heterogeneity that is associated with distinct physiological effects. A variety of allosteric ligands can modulate the response to GABA by binding at different sites on the GABAA-R complex. The best characterized binding site is the benzodiazepine (BZ) one, which is located at the α/γ subunit interface. BZs are commonly used in therapy for their effects as anxiolytic, anticonvulsants, myorelaxants and hypnotics. The broad range of pharmacological effects of classical BZs are mediated by the selective activation of different GABAA-R subtypes: the α1 subunit containing BZ receptor (BZ-R) mediates sedation, the α2 and α3 subunit containing BZ-R mediates anxiolysis and myorelaxation, and the α5 subunit containing BZ-R mediates cognitive impairment. Based on the current understanding of the diversity of the GABAA-R family, different approaches have been employed to develop drugs that target the GABAA/BZ-R complex with selective anxiolytic action and improved profiles. In this review, we present current knowledge about the role of the GABAA/BZ-R complex in anxiety disorders, new insights into the molecular biology of the receptor complex, and the importance of this target in the development of new therapeutic agents in anxiety.
焦虑症与γ-氨基丁酸(GABA)神经传递的改变有关。GABA 与配体门控离子通道 GABAA 受体(GABAA-R)亚型相互作用,调节氯离子流入细胞,导致神经元超极化。GABAA-R 由一组 19 个同源亚基基因产物组成,并形成主要的异源寡聚五聚体。GABAA-R 的主要亚型包含α、β和γ亚基,并表现出与不同生理效应相关的区域异质性。各种变构配体可以通过与 GABAA-R 复合物上的不同位点结合来调节 GABA 的反应。最好表征的结合位点是苯二氮䓬(BZ)结合位点,位于α/γ亚基界面。BZs 通常用于治疗焦虑症、抗惊厥、肌肉松弛和催眠,因为它们具有这些作用。经典 BZs 的广泛药理作用是通过对不同 GABAA-R 亚型的选择性激活来介导的:包含α1 亚基的 BZ 受体(BZ-R)介导镇静,包含α2 和α3 亚基的 BZ-R 介导抗焦虑和肌肉松弛,包含α5 亚基的 BZ-R 介导认知障碍。基于目前对 GABAA-R 家族多样性的理解,已经采用了不同的方法来开发靶向 GABAA/BZ-R 复合物的药物,这些药物具有选择性的抗焦虑作用和改善的特性。在这篇综述中,我们介绍了目前关于 GABAA/BZ-R 复合物在焦虑症中的作用、受体复合物的分子生物学新见解,以及该靶标在开发焦虑症新治疗药物中的重要性。