Anxiogenic-like activity of 3,4-methylenedioxy-methamphetamine ("Ecstasy") in the social interaction test is accompanied by an increase of c-fos expression in mice amygdala.
3,4-Methylenedioxymethamphetamine (MDMA) is a synthetic amphetamine popularly known as "Ecstasy." Animal studies examining acute effects of MDMA on anxiety are unclear because although an anxiolytic-like action of MDMA in different animal models of anxiety has been described, there is also substantial evidence supporting an anxiogenic-like effect of this drug. To date, several studies have examined c-fos expression following MDMA administration in rats. However, there is no information about the MDMA-induced c-fos expression in mice previously tested in an animal model of anxiety. In this study, male mice were injected with MDMA (1, 8 and 15 mg/kg ip) and assessed for changes on anxiety and for the expression of the immediate early gene c-fos in the amygdala (central, basolateral and basomedial). Anxiety was evaluated by the "social interaction test." Ten behavioral categories were recorded: body care, digging, nonsocial exploration, exploration from a distance, social investigation, threat, attack, avoidance/flee, defense/submission and immobility. As compared with the control group, mice treated with MDMA (all doses) showed a decrease in mean duration and total time spent in social investigation behaviors, whereas avoidance/flee behaviors were significantly increased after treatment with this compound (8 and 15 mg/kg). Likewise, a significant increase in c-fos expression was found in the basolateral (all doses) and central (15 mg/kg) amygdala after MDMA administration. Overall, these findings indicate that MDMA exhibits an anxiogenic-like profile in the social interaction test in mice, and that central and basolateral amygdala might be involved in these anxiogenic-like effects of the drug.
Navarro
José Francisco
JF
Department of Psychobiology, Faculty of Psychology, University of Málaga, Campus de Teatinos, s/n 29071 Málaga, Spain. navahuma@uma.es
Rivera
Alicia
A
Maldonado
Enrique
E
Cavas
María
M
de la Calle
Adelaida
A
D000679:Amygdala / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D001522:Behavior, Animal; D002452:Cell Count / Q000379:methods; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects; D006213:Hallucinogens / Q000494:pharmacology*; D007150:Immunohistochemistry / Q000379:methods; D007398:Interpersonal Relations; D008297:Male; D051379:Mice; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D018709:Statistics, Nonparametric
D006213:Hallucinogens; D016760:Proto-Oncogene Proteins c-fos; D018817:N-Methyl-3,4-methylenedioxyamphetamine