Av. Terry et al., CHOLINERGIC CHANNEL ACTIVATOR, ABT-418, ENHANCES DELAYED-RESPONSE ACCURACY IN RATS, Drug development research, 40(4), 1997, pp. 304-312
The purpose of this study was to evaluate ABT-418, a recently develope
d isoxasole bioisostere of nicotine and cholinergic channel activator
(ChCA), in rats trained to perform a delayed-response task, the Delaye
d Stimulus Discrimination Task (DSDT). In dose-effect studies, ABT-418
improved DSDT performance, while mecamylamine decreased accuracy of t
he task. The improvements afforded by optimal doses of ABT-418 were fu
rther substantiated by repeated administration on a separate occasion.
Surprisingly, mecamylamine (1.0 mg/kg), when combined with optimal do
ses of ABT-418, failed to prevent improvements in accuracy of the task
, as it had in a previous study with nicotine. The basis for this effe
ct is unclear but may be related to the purported subtype selectivity
of ABT-418. None of the drug-induced changes in DSDT accuracy was moda
lity specific (i.e., whether the stimulus was the presented light or t
one), and none of the drug manipulations produced significant changes
in response latencies. Overall, the data confirm findings of previous
rodent and nonhuman primate studies, which indicate that the nicotinic
ligand has the potential to improve memory. (C) 1997 Wiley-Liss, Inc.