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Chronic DMI reduces thresholds for brain stimulation reward in the rat
D A Valentino1, A J Riccitelli, R L Dufresne
1Department of Psychology, University of Rhode Island, Kingston 02881-0808.
Pharmacology, Biochemistry, and Behavior
|May 1, 1991
Summary
Chronic antidepressant treatment, not acute, enhanced brain stimulation reward (BSR) in rats. This suggests antidepressants may stabilize reward pathways, indirectly improving mood in depression models.
Area of Science:
- Neuroscience
- Pharmacology
- Behavioral Science
Background:
- Brain stimulation reward (BSR) models are used to understand depression.
- Antidepressant treatments are hypothesized to modulate BSR.
Purpose of the Study:
- To investigate the effect of chronic versus acute antidepressant treatment on BSR.
- To validate BSR models in depression research.
Main Methods:
- Rats received chronic desmethylimipramine (antidepressant) or saline.
- BSR thresholds were measured using a novel rate-free method over baseline, treatment, and withdrawal periods.
- Dose-dependent effects of desmethylimipramine were assessed.
Main Results:
- Chronic treatment with desmethylimipramine, particularly at 10 and 20 mg/kg, significantly enhanced BSR responding.
- Effects were observed later in the treatment period (days 15 and 18).
- One dose (10 mg/kg) showed persistent effects after drug withdrawal, while another (20 mg/kg) returned to baseline.
Conclusions:
- Chronic antidepressant administration can modulate BSR, supporting its role in depression models.
- Antidepressants may indirectly enhance reward system function by stabilizing underlying homeostatic mechanisms.
- The observed effects were small, suggesting complex interactions within reward circuitry.