Involvement of the Dorsal Hippocampus 5-HT1A Receptors in the Regulation of Depressive-Like Behaviors in Hemiparkinsonian Rats.
Neuropsychobiology 2021;
79:198-207. [PMID:
31940619 DOI:
10.1159/000505212]
[Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 12/02/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND
Depression is one of the most common neuropsychiatric disturbances in Parkinson's disease (PD), but its pathophysiology is not definite. Lines of evidence have indicated that the hippocampus and serotonin 1A (5-HT1A) receptors are related to the regulation of depression.
OBJECTIVE
The purpose of the present study was to observe the effect of 5-HT1A receptors in the dorsal hippocampus (dHIP) on PD-related depression in rats.
METHODS
Unilateral 6-hydroxydopamine lesioning of the medial forebrain bundle (MFB) was used to establish the hemiparkinsonian rat model. The effects of intra-dHIP injection of the 5-HT1A receptor -agonist 8-hydroxy-2-(dipropylamino)tetralin hydrobromide (8-OH-DPAT) or antagonist WAY-100635 on depressive-like behaviors were observed in sucrose preference and forced swim tests in control and lesioned rats. Monoamine levels including dopamine (DA), 5-HT, and noradrenaline (NA) in depression-related brain regions were determined by a neurochemical method in all groups.
RESULTS
Behavioral results showed that MFB lesions induced depressive-like behaviors. Intra-dHIP injection of 8-OH-DPAT produced antidepressant effects, while WAY-100635 induced or increased the depressive-like behaviors in both control and the lesioned rats. Neurochemical results found that intra-dHIP injection of 8-OH-DPAT significantly increased DA and 5-HT levels in the medial prefrontal cortex (mPFC), lateral habenula (LHb), ventral hippocampus and amygdala in the lesioned group and decreased NA levels in the mPFC and LHb in the control group. Moreover, after injection of WAY-100635, NA levels in all these regions of the lesioned group were significantly increased.
CONCLUSIONS
These findings suggest that hippocampal 5-HT1A receptors regulate depression and PD-related depression by neurochemical mechanisms.
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