Brain stimulation and morphine reward deficits in dopamine D2 receptor-deficient mice
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.Get Access
The rewarding effects of lateral hypothalamic brain stimulation, various natural rewards, and several drugs of abuse are attenuated by D1 or D2 dopamine receptor (D1R or D2R) antagonists. Much of the evidence for dopaminergic involvement in rewards is based on pharmacological agents with limited or “relative” selectivity for dopamine receptor subtypes. Genetically engineered animal models provide a complementary approach to pharmacological investigations.
In the present study, we explored the contribution of dopamine D2Rs to (1) brain stimulation reward (BSR) and (2) the potentiation of this behavior by morphine and amphetamine using D2R-deficient mice.
Wild-type (D2Rwt), heterozygous (D2Rhet), and D2R knockout (D2Rko) mice were trained to turn a wheel for rewarding brain stimulation. Once equivalent rate–frequency curves were established, morphine-induced (0, 1.0, 3.0, and 5.6 mg/kg s.c.) and amphetamine-induced (0, 1.0, 2.0, and 4.0 mg/kg i.p.) potentiations of BSR were determined.
The D2Rko mice required approximately 50% more stimulation than the D2Rwt mice did. With the equi-rewarding levels of stimulation current, amphetamine potentiated BSR equally across the three genotypes. In contrast, morphine potentiated rewarding stimulation in the D2Rwt, had no effect in the D2Rhet, and antagonized rewarding stimulation in the D2Rko mice.
D2R elimination decreases, but does not eliminate, the rewarding effects of lateral hypothalamic stimulation. After compensation for this deficit, amphetamine continues to potentiate BSR, while morphine does not.
- Brain stimulation and morphine reward deficits in dopamine D2 receptor-deficient mice
Volume 182, Issue 1 , pp 33-44
- Cover Date
- Print ISSN
- Online ISSN
- Additional Links
- Industry Sectors
- Author Affiliations
- 1. Department of Psychiatry, Maryland Psychiatric Research Center, University of Maryland, Maple and Locust Streets, Baltimore, MD, 21228, USA
- 2. Behavioral Neuroscience, IRP, NIDA, NIH, Baltimore, MD, 21224, USA
- 3. INGEBI, University of Buenos Aires, Buenos Aires, Argentina
- 4. Vollum Institute and Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, 97239, USA
- 5. Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, 97239, USA