Effect of SCH 23390 on (+/-)-3,4-methylenedioxymethamphetamine hyperactivity and self-administration in rats.
Recently, we demonstrated that (+/-)-3,4-methylenedioxymethamphetamine (MDMA; ecstasy) was reliably and dose-dependently self-administered by previously drug-naïve laboratory rats. The neurochemical basis of MDMA self-administration has not, however, been extensively studied. The present study investigated the role of dopamine in MDMA self-administration and hyperactivity. Pretreatment with the D1-like antagonist, SCH 23390 (0.01-0.08 mg/kg) produced a dose-dependent attenuation of MDMA (20.0 mg/kg)-produced hyperactivity. In self-administration tests, the baseline rate of responding maintained by intravenous infusions varied inversely with MDMA dose; as the dose available was changed, responding also changed so that about 10.0 mg/kg MDMA was self-administered during each daily 2-h session. Pretreatment with SCH 23390 (0.02 mg/kg) produced a rightward shift in the MDMA dose-response curve. These findings suggest that MDMA self-administration, like self-administration of other drugs of abuse, is dependent on the activation of dopaminergic substrates.
Daniela
Evangelene
E
School of Psychology, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
Brennan
Katie
K
Gittings
Dave
D
Hely
Lincoln
L
Schenk
Susan
S
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006948:Hyperkinesis / Q000139:chemically induced* / Q000517:prevention & control*; D008297:Male; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000008:administration & dosage* / Q000037:antagonists & inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D012646:Self Administration
D001552:Benzazepines; D018817:N-Methyl-3,4-methylenedioxyamphetamine