Sex Differences in Cocaine-Stimulated Motor Behavior: Disparate Effects of Gonadectomy

• Published in: Neuropsychopharmacology (New York, N.Y.) Vol. 25; no. 1; pp. 118 - 130
• Main Authors: Walker, Q.David, Cabassa, Jose, Kaplan, Karly A, Li, Shih-Tzung, Haroon, Jennifer, Spohr, Hilmar A, Kuhn, Cynthia M
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-07-2001; Nature Publishing; Nature Publishing Group
• Subjects: Amphetamines; Animals; Behavior; Behavior, Animal - drug effects; Behavior, Animal - physiology; Behavioral psychophysiology; Biological and medical sciences; Cocaine; Cocaine - pharmacology; Cocaine-Related Disorders - physiopathology; Data Interpretation, Statistical; Dopamine Uptake Inhibitors - pharmacology; Dose-Response Relationship, Drug; Drug addictions; Female; Females; Fundamental and applied biological sciences. Psychology; Gender differences; Gonadal hormones; Gonadal Steroid Hormones - metabolism; Hormones; Hormones and behavior; Laboratories; Locomotion; Male; Males; Medical sciences; Motor Activity - drug effects; Motor Activity - physiology; Oophorectomy; Orchiectomy - adverse effects; Ovariectomy - adverse effects; Ovaries; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Psychostimulant; Rats; Rats, Sprague-Dawley; Rearing; Sex Characteristics; Stereotyped Behavior - drug effects; Stereotyped Behavior - physiology; Stereotypy; Steroids - metabolism; Toxicology; Women; Locomotion; Gonadal hormones; Rearing; Psychostimulant; Stereotypy; Drug addiction; Intraperitoneal administration; Ovariectomy; Rat; CNS stimulant; Illicit drug; Psychotropic; Toxicity; Rodentia; Sex; Open field behavior; Dose activity relation; Ester; Vertebrata; Mammalia; Spontaneous physical activity; Castration; Animal; Cocaine; Drug of abuse; Estrous cycle; Sex steroid hormone
• ISSN: 0893-133X; 1740-634X
• DOI: 10.1016/S0893-133X(00)00248-7

Sex differences in biological substrates of drug use and addiction are poorly understood. The present study investigated sexual dimorphisms in motor behavior following acute cocaine administration (10, 20, or 40 mg/kg, i.p.). Cocaine increased stereotypy rating, horizontal and vertical activity in both sexes, and effects were always greater in females than males. A population analysis using data from multiple experiments indicated that horizontal activity scores were normally distributed in males but not in females. Gonadectomy induced disparate effects on cocaine-stimulated motor behavior. Population analysis indicated that castrated males exhibited more horizontal activity and stereotypy than shams. Ovariectomy did not affect cocaine-stimulated stereotypy but did attenuate horizontal activity in a subset of rats that had not been vaginally lavaged. In summary, gonadectomy effects were sex and behavioral topography specific and indicate that activational effects of gonadal hormones partially mediate the robust sex differences in cocaine-stimulated open-field behavior.