title: Environmental enrichment preceding early adulthood methylphenidate treatment leads to long term increase of corticosterone and testosterone in the rat.
abstract: Attention-deficit/hyperactivity disorder (ADD/ADHD) has been emerging as a world-wide psychiatric disorder. There appears to be an increasing rate of stimulant drug abuse, specifically methylphenidate (MPH) which is the most common treatment for ADHD, among individuals who do not meet the criteria for ADHD and particularly for cognitive enhancement among university students. However, the long term effects of exposure to MPH are unknown. Thus, in light of a developmental approach in humans, we aimed to test the effects of adolescence exposure to enriched environment (EE) followed by MPH administration during early adulthood, on reactions to stress in adulthood. Specifically, at approximate adolescence [post natal days (PND) 30-60] rats were reared in EE and were treated with MPH during early adulthood (PND 60-90). Adult (PND 90-92) rats were exposed to mild stress and starting at PND 110, the behavioral and endocrine effects of the combined drug and environmental conditions were assessed. Following adolescence EE, long term exposure to MPH led to decreased locomotor activity and increased sucrose preference. EE had a beneficial effect on PPI (attentive abilities), which was impaired by long term exposure to MPH. Finally, the interaction between EE and, exposure to MPH led to long-term elevated corticosterone and testosterone levels. In view of the marked increase in MPH consumption over the past decade, vigilance is crucial in order to prevent potential drug abuse and its long term detrimental consequences.
authors.affiliation: Department of Psychology and the Center for Psychobiological Research, The Yezreel Valley College, Yezreel Valley, Israel.
authors.forename: Avi
authors.initials: A
authors.lastname: Avital
authors.forename: Talya
authors.initials: T
authors.lastname: Dolev
authors.forename: Shlomit
authors.initials: S
authors.lastname: Aga-Mizrachi
authors.forename: Salman
authors.initials: S
authors.lastname: Zubedat
mesh_terms: D000375:Aging / Q000187:drug effects*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003345:Corticosterone / Q000097:blood*; D004777:Environment; D005615:Freezing; D008124:Locomotion / Q000187:drug effects; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage / Q000494:pharmacology*; D010812:Physical Stimulation; D051381:Rats; D017208:Rats, Wistar; D012201:Reward; D013312:Stress, Physiological / Q000187:drug effects; D013739:Testosterone / Q000097:blood*; D013997:Time Factors
chemical_list: D008774:Methylphenidate; D013739:Testosterone; D003345:Corticosterone