Chronic methylphenidate treatment enhances water maze performance following traumatic brain injury in rats

Methylphenidate (MPH), a central nervous system stimulant with dopaminergic activity, facilitates neurobehavioral outcome following cortical suction a blation injury, but its potential efficacy following experimental traumatic brain injury (TBI) is unknown. Thus, beginning 24 h after controlled corti cal impact injury or sham surgery, male Sprague-Dawley rats were injected ( i.p.) once daily for 18 days with either MPH (5 mg/kg) or saline vehicle (V EH) and motor function assessed on post-operative days 1-4, followed by Mor ris water maze training to find a hidden platform on days 14-18. The MPH tr eatment regimen was ineffective in accelerating beam-balance or beam-walk r ecovery, but did significantly decrease swim latencies when compared to VEH -treated controls. The results are consistent with published studies showin g improved outcome with MPH therapy. Furthermore, this positive finding wit h delayed treatment suggests that strategies that enhance catecholamine neu rotransmission during the chronic post injury phase may be a useful adjunct in ameliorating some of the neurobehavioral sequelae following TBI in huma ns. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.