CHOLINERGIC MECHANISMS IN STARTLE AND PREPULSE INHIBITION - EFFECTS OF THE FALSE CHOLINERGIC PRECURSOR N-AMINODEANOL

We examined the effects of cholinergic deficiency on prepulse inhibiti on (PPI) of the acoustic startle. Rats treated with a choline-free die t that contained the false cholinergic precursor N-aminodeanol showed great deficit in PPI. This deficit does not appear to he secondary to an increase ot stereotyped behaviors. Startle threshold was also great ly reduced, as these rats startled to the 70-dB prepulse and the basel ine startle amplitude was increased by 60% over the control rats. Arec oline (4 mg/kg) partially reversed the deficit in PPI. This improvemen t persisted beyond the period of drug treatment. On the other hand, sc opolamine (1 mg/kg) reduced PPI in the control rats. These results sug gest that cholinergic systems play a major role in both the elicitatio n and prepulse inhibition of startle.