The role of serotonin and dopamine in brain in the antidepressant-like effect of clonidine in the forced swimming test.
The effect of clonidine (0.1 mg/kg, i.p.), as a three-injection course, on behaviour in the forced swimming test was studied in rats injected intracerebroventricularly (i.c.v.) with 150 micrograms 5,7-dihydroxy-tryptamine (5,7-DHT) to destroy serotonin (5-HT) neurones or treated with 100 mg/kg (i.p.) (+/-)-sulpiride or 0.5 micrograms/0.5 microliter (-)-sulpiride in the nucleus accumbens. Clonidine significantly increased struggling and reduced floating and the effects were antagonized by both treatments with sulpiride but not by 5,7-DHT which markedly depleted 5-HT in brain. The results suggest that the mesolimbic dopaminergic system but not 5-HT neurones, plays a permissive role in the antidepressant-like effect of clonidine in the forced swimming test.
Cervo
L
L
Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
Rossi
C
C
Samanin
R
R
D015116:5,7-Dihydroxytryptamine / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D003000:Clonidine / Q000494:pharmacology*; D004298:Dopamine / Q000502:physiology*; D007276:Injections, Intraventricular; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000502:physiology*; D013315:Stress, Psychological / Q000503:physiopathology*; D013469:Sulpiride / Q000494:pharmacology; D013550:Swimming
D000928:Antidepressive Agents; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D013469:Sulpiride; D003000:Clonidine; D004298:Dopamine