Lack of Delayed Effects of Amphetamine, Methoxamine, and Prazosin (Adrenergic Drugs) on Behavioral Outcome after Lateral Fluid Percussion Brain Injury in the Rat

Abstract

This study examined the delayed effects of the administration of d-amphetamine, methoxamine (an alpha1-adrenergic receptor agonist), and prazosin (an alpha1-adrenergic receptor antagonist) on the behavioral outcome of lateral fluid-percussion (FP) brain injury. Rats trained to perform a beam-walking task were subjected to brain injury of moderate severity (2.1 to 2.2 atm). Twenty-four hours after injury, rats were treated with amphetamine, methoxamine, or prazosin at two or three different dose levels. Amphetamine-treated animals displayed no significant improvement in beam-walking ability either during or after drug intoxication (from days 3 to 5 after brain injury). Similarly, neither methoxamine nor prazosin significantly affected beam-walking ability during or after drug intoxication. Neither amphetamine treatment at three different doses nor treatment with methoxamine or prazosin at two different doses affected the spatial learning disabilities of brain-injured animals. These results suggest that (1) unlike amphetamine administration after sensorimotor cortex (SMC) ablation or contusion brain injury models, amphetamine administration at 24 h after concussive FP brain injury does not improve beam-walking performance; (2) unlike amphetamine administration 10 min after concussive FP brain injury amphetamine administration 24 h after injury does not improve cognitive function; and (3) unlike prazosin administration after SMC ablation brain injury, prazosin administration 24 h after concussive FP brain injury does not effect beam-walking performance.

Fibroblast Growth Factor-18 Reduced Infarct Volumes and Behavioral Deficits After Transient Occlusion of the Middle Cerebral Artery in Rats

“…Motor performance was evaluated with the beam walk test. 16 The time required to traverse the beam was converted to an ordinal scale: latencies for all 3 trials Ͻ10 secondsϭ1.0; latencies for all 3 trials Ͼ10 and Ͻ25 secondsϭ2.0; latencies for all 3 trials Ͼ25 and Ͻ60 secondsϭ3.0; failure to complete all 3 trials but completion of 1 or 2 with latencies Ͻ25 secondsϭ4.0; failure to complete all 3 trials but completion of 1 or 2 with latencies Ͼ25 secondsϭ5.0; and failure to complete all trialsϭ6.0.…”

Time Window of Fibroblast Growth Factor-18—Mediated Neuroprotection after Occlusion of the Middle Cerebral Artery in Rats*

“…Motor performance was evaluated using the beam walk test (Dose et al, 1997). The time required to traverse the beam was converted to an ordinal scale: latencies for all three trials < 10 seconds = 1; latencies > 10 seconds < 25 seconds for all three trials = 2; latencies for all three trials > 25 seconds and < 60 seconds = 3; failure to complete all three trials but completion of one or two with latencies < 25 seconds = 4; failure to complete all three trials but completion of one or two with latencies > 25 seconds = 5; failure to complete all trials = 6.…”

Outcome from traumatic brain injury

“…Mu opioid receptors have been investigated and receptor agonists appear to increase motor deficits, whereas antagonists improve motor function, when given prior to injury in an animal model [186]. The α1-adrenoreceptor antagonist prazosin may increase excitatory transmission and has been shown to worsen behavioral and motor deficits in rats [187], but these results were not confirmed in another study [188].…”