Neurochemical and behavioral effects of 8-OH-DPAT following exposure to restraint stress in rats.
8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a selective 5-hydroxytryptamine 1A (serotonin; 5-HT1A) agonist was used to evaluate the role of somatodendritic and/or postsynaptic 5-HT1A receptors following exposure to restraint stress. Exposure to an episode of 2-h restraint stress decreased 24 h cumulative food intake. Intensity of 8-OH-DPAT-induced 5-HT syndrome monitored next day was smaller in restrained than unrestrained animals. Hyperphagic effects of 8-OH-DPAT were comparable in the two groups. Restrained animals injected with saline exhibited an increase in 5-HT levels in the hippocampus, hypothalamus and cortex but not in the midbrain and striatum. 5-Hydroxyindolacetic acid (5-HIAA) increased in the hippocampus, midbrain and cortex but not in the hypothalamus and striatum. 8-OH-DPAT injected at a dose of 0.25 mg/kg decreased 5-HT and 5-HIAA levels in different brain regions of unrestrained as well as restrained animals. The decreases were greater in restrained than unrestrained animals, suggesting a supersensitivity of somatodendritic 5-HT1A receptors. The results are discussed in the context of a role of 5-HT1A receptor in restraint-induced behavioral deficits.
Samad
Noreen
N
Department of Biochemistry, Neurochemistry and Biochemical Neuropharmacology Research Laboratory, University of Karachi, Karachi-75270, Pakistan. noreensamad_ku@yahoo.com
Batool
Farhat
F
Haleem
Darakhshan J
DJ
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology*; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D006897:Hydroxyindoleacetic Acid / Q000032:analysis; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D044282:Receptor, Serotonin, 5-HT1A / Q000502:physiology*; D012149:Restraint, Physical; D012701:Serotonin / Q000032:analysis; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013315:Stress, Psychological / Q000378:metabolism* / Q000523:psychology*
D017366:Serotonin Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin