title: Activation of 5-HT₁A receptors in the medial subdivision of the central nucleus of the amygdala produces anxiolytic effects in a rat model of Parkinson's disease.
abstract: Although the medial subdivision of the central nucleus of the amygdala (CeM) and serotonin-1A (5-HT1A) receptors are involved in the regulation of anxiety, their roles in Parkinson's disease (PD)-associated anxiety are still unknown. Here we assessed the importance of CeM 5-HT1A receptors for anxiety in rats with unilateral 6-hydroxydopamine (6-OHDA) lesion of the medial forebrain bundle (MFB). The lesion induced anxiety-like behaviors, increased the firing rate and burst-firing pattern of CeM γ-aminobutyric acid (GABA) neurons, as well as decreased dopamine (DA) levels in the striatum, medial prefrontal cortex (mPFC), amygdala and ventral part of hippocampus (vHip). Intra-CeM injection of the selective 5-HT1A receptor agonist 8-OH-DPAT produced anxiolytic effects in the lesioned rats, and decreased the firing rate of CeM GABAergic neurons in two groups of rats. Compared to sham-operated rats, the duration of the inhibitory effect on the firing rate of GABAergic neurons was shortened in the lesioned rats. The injection increased DA levels in the mPFC and amygdala in two groups of rats and the vHip in the lesioned rats, and increased 5-HT level in the lesioned rats, whereas it decreased NA levels in the mPFC in two groups of rats and the vHip in the lesioned rats. Moreover, the mean density of 5-HT1A receptor and GABA double-labeled neurons in the CeM was reduced after the lesioning. These results suggest that activation of CeM 5-HT1A receptor produces anxiolytic effects in the 6-OHDA-lesioned rats, which involves decreased firing rate of the GABAergic neurons, and changed monoamine levels in the limbic and limbic-related brain regions.
authors: Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors: Yi-Na
authors: YN
authors: Sun
authors: Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors: Tao
authors: T
authors: Wang
authors: Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors: Yong
authors: Y
authors: Wang
authors: Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors: Ling-Na
authors: LN
authors: Han
authors: Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors: Li-Bo
authors: LB
authors: Li
authors: Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
authors: Yu-Ming
authors: YM
authors: Zhang
authors: Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China. Electronic address: liujian@mail.xjtu.edu.cn.
authors: Jian
authors: J
authors: Liu
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001008:Anxiety Disorders / Q000188:drug therapy* / Q000503:physiopathology; D066274:Central Amygdaloid Nucleus / Q000187:drug effects* / Q000503:physiopathology; D004298:Dopamine / Q000378:metabolism; D059330:GABAergic Neurons / Q000187:drug effects / Q000502:physiology; D008032:Limbic System / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D008474:Medial Forebrain Bundle / Q000503:physiopathology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D016627:Oxidopamine; D020734:Parkinsonian Disorders / Q000503:physiopathology* / Q000523:psychology; D010879:Piperazines / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D017207:Rats, Sprague-Dawley; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism; D058825:Serotonin 5-HT1 Receptor Agonists / Q000494:pharmacology*; D058829:Serotonin 5-HT1 Receptor Antagonists / Q000494:pharmacology
chemical_list: D014151:Anti-Anxiety Agents; D010879:Piperazines; D011725:Pyridines; D058825:Serotonin 5-HT1 Receptor Agonists; D058829:Serotonin 5-HT1 Receptor Antagonists; D044282:Receptor, Serotonin, 5-HT1A; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D016627:Oxidopamine; D004298:Dopamine
keywords: 5-HT(1A) receptor; Anxiety; Central nucleus of the amygdala; GABAergic neurons; In vivo electrophysiology; Parkinson's disease