Fluoxetine potentiates the effects of corticotropin-releasing factor on locomotor activity and serotonergic systems in the roughskin newt, Taricha granulosa.

Full Abstract

The anxiety- and stress-related neuropeptide corticotropin-releasing factor (CRF) elicits behavioral changes in vertebrates including increases in behavioral arousal and locomotor activity. Intracerebroventricular injections of CRF in an amphibian, the roughskin newt (Taricha granulosa), induces rapid increases in locomotor activity in both intact and hypophysectomized animals. We hypothesized that this CRF-induced increase in locomotor activity involves a central effect of CRF on serotonergic neurons, based on known stimulatory actions of serotonin (5-hydroxytryptamine, 5-HT) on spinal motor neurons and the central pattern generator for locomotor activity in vertebrates. In Experiment 1, we found that neither intracerebroventricular injections of low doses of CRF (25 ng) nor the selective serotonin reuptake inhibitor fluoxetine (10, 100 ng), by themselves, altered locomotor activity. In contrast, newts treated concurrently with CRF and fluoxetine responded with marked increases in locomotor activity. In Experiment 2, we found that increases in locomotor activity following co-administration of CRF (25 ng) and fluoxetine (100 ng) were associated with decreased 5-HT concentrations in a number of forebrain structures involved in regulation of emotional behavior and emotional states, including the ventral striatum, amygdala pars lateralis, and dorsal hypothalamus, measured 37 min after treatment. These results are consistent with the hypothesis that CRF stimulates locomotor activity through activation of serotonergic systems.

Author information

Author/s: Lowry, Christopher A (CA); Hale, Matthew W (MW); Burke, Kathleen A (KA); Renner, Kenneth J (KJ); Moore, Frank L (FL);

Affiliation: Department of Zoology, Oregon State University, Corvallis, OR 97331, USA. christopher.lowry(-atsign-)colorado.edu

Grants: 1F31MH10288-01A1 (Agency:NIMH NIH HHS) ; MH-44893 (Agency:NIMH NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.

Journal: Hormones and behavior (Horm Behav), published in United States. (Language: eng)

Reference: 2009-Jun; vol 56 (issue 1) : pp 177-84

Dates: Created 2009/06/01; Completed 2009/08/21;

PMID: 19409390, status: MEDLINE (last retrieval date: 8/21/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Male
Motor Activity - drug effects; physiology
Prosencephalon - drug effects; metabolism
Radioimmunoassay
Salamandridae - physiology
Serotonin - metabolism
Serotonin Uptake Inhibitors - administration & dosage

Associated Chemicals: Serotonin Uptake Inhibitors (0) ; Corticosterone (50-22-6) ; Serotonin (50-67-9) ; Hydroxyindoleacetic Acid (54-16-0) ; Fluoxetine (54910-89-3) ; Corticotropin-Releasing Hormone (9015-71-8)

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