title: Sex differences in abuse-related neurochemical and behavioral effects of 3,4-methylenedioxymethamphetamine (MDMA) in rats.
abstract: 3,4-Methylenedioxymethamphetamine (MDMA) is a substrate for dopamine (DA), norepinephrine and serotonin (5HT) transporters that produces greater pharmacological effects on certain endpoints in females than males in both clinical and rodent preclinical studies. To evaluate potential for sex differences in abuse-related MDMA effects, the present study compared MDMA effects on intracranial self-stimulation (ICSS) and on in vivo microdialysis measurements of DA or 5HT in the nucleus accumbens (NAc) in female and male Sprague-Dawley rats. For ICSS studies, electrodes were implanted in the medial forebrain bundle and rats trained to press for electrical stimulation over a range of frequencies (56-158Hz, 0.05 log increments) under a fixed-ratio 1 schedule, and the potency (0.32-3.2mg/kg, 10min pretreatment) and time course (3.2. mg/kg, 10-180min pretreatment) of MDMA effects were determined. For in vivo microdialysis, rats were implanted with bilateral guide cannulae targeting the NAc, and the time course of MDMA effects (1.0-3.2mg/kg, 0-180min) on DA and 5HT was determined. MDMA produced qualitatively similar effects in both sexes on ICSS (both increases in low ICSS rates maintained by low brain-stimulation frequencies and decreases in high ICSS rates maintained by high brain-stimulation frequencies) and microdialysis (increases in both DA and 5HT). The duration and peak levels of both abuse-related ICSS facilitation and increases in NAc DA were longer in females. MDMA was also more potent to increase 5HT in females. These results provide evidence for heightened sensitivity of females to abuse-related behavioral and neurochemical effects of MDMA in rats.
authors: Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA. Electronic address: lazenkamf@mymail.vcu.edu.
authors: M F
authors: MF
authors: Lazenka
authors: Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA.
authors: J A
authors: JA
authors: Suyama
authors: Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA.
authors: C T
authors: CT
authors: Bauer
authors: Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298, USA.
authors: M L
authors: ML
authors: Banks
authors: Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298, USA.
authors: S S
authors: SS
authors: Negus
mesh_terms: D000818:Animals; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D008474:Medial Forebrain Bundle / Q000502:physiology; D017551:Microdialysis; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000378:metabolism; D051381:Rats; D012653:Self Stimulation / Q000187:drug effects; D012701:Serotonin / Q000378:metabolism; D012727:Sex Characteristics; D013997:Time Factors
chemical_list: D012701:Serotonin; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D004298:Dopamine
keywords: ICSS; MDMA; Microdialysis; Sex difference