Oral
administration of adrafinil improves discrimination learning in aged beagle
dogs.
Milgram NW, Siwak CT, Gruet P,
Atkinson P, Woehrle F, Callahan H
Division of Life Sciences,
University of Toronto at Scarborough,
1265 Military
Trail, Ontario, M1C 1A4, Scarborough, Canada.
Pharmacol Biochem Behav 2000 Jun;66(2):301-5
ABSTRACT
Aged beagle dogs were trained on either a size or intensity discrimination
task 2 h following treatment with either 20 mg/kg of adrafinil or a placebo
control. Training continued until the dogs reached a predetermined
criterion level of performance, or failed to acquire the task after 40
sessions. The treatments and tasks were then reversed, with both the
test order and treatment order counterbalanced. Thus, half of the
animals were first tested on the intensity discrimination, and half of these
were first tested under adrafinil. Treatment with adrafinil produced
significant improvement in learning, as indicated by a decrease in both
errors and trials to criterion. An effect of adrafinil on motivation may
partially account for these findings; however, adrafinil did not significantly
affect response latency. Adrafinil is believed to serve as an alpha-1
adrenoceptor agonist. The improved learning may also result from
enhancement of vigilance due to facilitation of noradrenergic transmission in
the central nervous system..