Evaluation of a cholinomimetic drug, 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta [b] quinoline (NIK-247), as an enhancer of endogenous efflux of acetylcholine from brain slices.

Basal and high K(+)-stimulated efflux of endogenous ACh from slices of brain was measured to evaluate the cholinomimetic effect of 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b] quinoline monohydrate HCl (NIK-247) on the central nervous system. The drug NIK-247 dose-dependently accelerated the efflux of ACh from slices of striatum. The maximum increase produced by 1.0 x 10(-4) M of NIK-247 was 329% in basal and 1332% in 30 mM K(+)-stimulated efflux. This drug was nearly twice as potent as THA (9-amino-1,2,3,4-tetrahydroacridine HCl) but had the same potency as physostigmine, in enhancing basal efflux, although there was no significant difference between the efficacy of these drugs in enhancing the K(+)-stimulated efflux. Both basal and 50 mM K(+)-stimulated efflux of ACh were increased by NIK-247, not only from the striatum but also from slices of frontal cortex and hippocampus. The activity was more effective in the striatum than in other tissues, and more effective on K(+)-stimulated than on basal efflux, regardless of the region of the brain. These effects of NIK-247 may be a result mainly of its inhibition of cholinesterase and its other biological characteristics, such as K+ channel blockade, capable of modulating release of ACh, may not be of major importance.