Effects of the nicotinic antagonist mecamylamine on inspection time

Rationale: Several lines of evidence suggest that nicotinic acetylcholine r eceptors (nAchRs) are involved in speed of information processing, and insp ection time appears to be particularly sensitive to nicotinic manipulation. Objective: The present study sought to examine the effects of the nAchR an tagonist mecamylamine on inspection time. Furthermore, the extent to which the anticholinesterase donepezil would reverse the effects of mecamylamine on inspection time was also examined. Methods: A double-blind, repeated mea sures design was employed. Subjects (n=6) received placebo, mecamylamine (2 0 mg PO) or mecamylamine (20 mg PO) and donepezil (5 mg PO). Inspection tim e and physiological measures were then assessed. Results: The mecamylamine condition and the mecamylamine and donepezil condition were associated with an increase in heart rate, when compared to the placebo condition. There w as a significant slowing of inspection time in the mecamylamine condition, compared to placebo, which was partly reversed by donepezil. Conclusions: T he slowing of inspection time following mecamylamine is consistent with the role of nAchRs in speed of information processing, and add to the evidence that IT may in part index nAchR system integrity.