Serotonin type-1A receptors modulate adolescent, cocaine-induced offensive aggression in hamsters.
Hamsters repeatedly exposed to cocaine throughout adolescence display highly escalated offensive aggression compared to saline-treated littermates. Recently, we have shown that serotonin neural signaling and development play an important role in adolescent cocaine-induced offensive aggression. This study examined whether the adolescent cocaine-induced aggressive response was modulated by serotonin type 1A (5HT1A) receptors. To test this, adolescent male Syrian hamsters were administered cocaine hydrochloride (0.5 mg/kg, i.p.) throughout adolescent development (P27-57) and then tested for offensive aggression after the administration of the 5HT(1A) receptor agonist R(+)-8-OH-DPAT (0.1, 0.3, 0.6, 1.0, 1.25 mg/kg, i.p.). R(+)-8-OH-DPAT dose-dependently reduced cocaine-induced offensive aggression, with a significant reduction observed at 0.3 mg/kg for most of the offensive responses measured. Animals treated with higher doses of R(+)-8-OH-DPAT (0.6-1.25 mg/kg) prior to testing showed significant reductions in all measures of offensive aggression and social interest towards intruders (i.e., contact time), indicating more general behavioral inhibition. Adolescent cocaine-treated animals did not differ in body weight from controls, suggesting that the increased aggression was not due to increased body mass. These data support a role for 5HT1A signaling in adolescent cocaine-induced aggression.
Knyshevski
Irina
I
Behavioral Neuroscience Program, Department of Psychology, 125 Nightingale Hall, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
Ricci
Lesley A
LA
McCann
Thomas E
TE
Melloni
Richard H
RH
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000367:Age Factors; D000374:Aggression / Q000187:drug effects*; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal / Q000187:drug effects; D003042:Cocaine / Q000494:pharmacology*; D006224:Cricetinae; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D008297:Male; D011930:Reaction Time / Q000187:drug effects; D044282:Receptor, Serotonin, 5-HT1A / Q000502:physiology*; D018490:Serotonin Agents / Q000494:pharmacology; D013997:Time Factors
D018765:Dopamine Uptake Inhibitors; D018490:Serotonin Agents; D044282:Receptor, Serotonin, 5-HT1A; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D003042:Cocaine