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Author Notes:

Correspondence: Jay M. Weiss, Ph.D. Emory University School of Medicine Emory Briarcliff Campus Building A, Room 510N 1256 Briarcliff Road, N.E. Atlanta, GA 30306; Tel: 404-712-9771; Fax: 404-712-9755; Email: jweis01@emory.edu

Subjects:

Research Funding:

This research was supported in part by Public Health Service grants MH065737 and MH079794.

Keywords:

  • galanin
  • norepinephrine
  • locus coeruleus
  • ventral tegmentum
  • antidepressant
  • desipramine
  • paroxetine
  • phenelzine

Influence of Chronic Administration of Antidepressant Drugs on mRNA for Galanin, Galanin Receptors, and Tyrosine Hydroxylase in Catecholaminergic and Serotonergic Cell-body Regions in Rat Brain

Tools:

Journal Title:

Neuropeptides

Volume:

Volume 46, Number 2

Publisher:

, Pages 81-91

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Activity of locus coeruleus (LC) neurons and release of the peptide galanin (GAL), which is colocalized with norepinephrine (NE) in LC neurons, has been implicated in depression and, conversely, in antidepressant action. The present study examined the influence of chronic administration (for 14 days, via subcutaneously-implanted minipump) of antidepressant (AD) drugs representing three different classes (tricyclic [desipramine], selective serotonin reuptake inhibitor [SSRI] [paroxetine], and monoamine oxidase inhibitor [MAOI] [phenelzine]) on mRNA for GAL, GAL receptors (GalR1, R2, and R3), and tyrosine hydroxylase (TH), the rate-limiting enzyme for NE synthesis, in four brain regions – LC, A1/C1, dorsal raphe (DRN), and ventral tegmentum (VTA) of rats. Consistent with previous findings that chronic administration of AD drugs decreases activity of LC neurons, administration of AD drugs reduced mRNA for both GAL and TH in LC neurons. GAL and TH mRNA in LC neurons was highly correlated. AD drugs also reduced GAL and TH mRNA in A1/C1 and VTA but effects were smaller than in LC. The largest change in mRNA for GAL receptors produced by AD administration was to decrease mRNA for GalR2 receptors in the VTA region. Also, mRNA for GalR2 and GalR3 receptors was significantly (positively) correlated in all three predominantly catecholaminergic brain regions (LC, A1/C1, and VTA). Relative to these three brain regions, unique effects were seen in the DRN region, with the SSRI elevating GAL mRNA and with mRNA for GalR1 and GalR3 being highly correlated in this brain region. The findings show that chronic administration of AD drugs, which produces effective antidepressant action, results in changes in mRNA for GAL, GAL receptors, and TH in brain regions that likely participate in depression and antidepressant effects.

Copyright information:

© 2012 Elsevier Ltd. All rights reserved.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported License (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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