Raymond Traweek, Reyes-Vasquez C and Dafny N
The University of Texas McGovern Medical School, USA
Posters & Accepted Abstracts: Neurochem Neuropharm
Attention deficit hyperactivity disorder (ADHD) is a complex behavioral and psychiatric disorder characterized by hyperactivity, increased impulsivity and inattention, though the precise neurophysiology remains unclear. Currently, methylphenidate (MPD) is one of the most commonly prescribed psychostimulants for management and treatment of ADHD. A rise in the consumption of MPD in the healthy population has prompted concern regarding the ontogenic effects of acute and chronic MPD exposure. The objective of this study is to concomitantly record behavioral and neuronal activity for the dorsal raphe (DR), a major source of serotonergic innervation in the mammalian brain, following the dose-response protocol of acute and chronic administration of MPD in freely behaving adult and adolescent rats. Four groups of rats were used: Saline (control), 0.6, 2.5 and 10.0, mg/kg MPD. The experiment lasted 10 consecutive days. Animals received MPD injections on experimental days 1-6, followed by three washout days and a rechallenge with the same MPD dosage on experimental day 10 (ED10). It was found that most of the DR units responded to MPD exposure and that the recordings obtained from adolescent rats exhibited different response patterns compared to the recordings obtained from adult rats. Additionally, the DR units of behaviorally sensitized animals exhibited a significant (p<0.05) difference in response to MPD rechallenge on ED10 as compared to the DR units of behaviorally tolerant animals. Furthermore, it was found that the ratio of the number of animals exhibiting behavioral sensitization to the number of animals exhibiting behavioral tolerance in adolescents showed a significant (p<0.05) difference from the ratio of behavioral sensitization to tolerance in adult animals. In conclusion, these correlations suggest that the effect of MPD on adolescents is different than the effect of MPD on adults and that the DR of both adolescents and adults participate in MPD action.
Raymond Traweek is currently a Medical student at McGovern Medical School at the University of Texas Health Science Center at Houston. He is currently pursuing his MD alongside a scholarly concentration in Medical Humanities.
Email: Raymond.Traweek@uth.tmc.edu
