Differential effects of physostigmine and 1,2,3,4-tetrahydro-9-aminoacridine on the ß-adrenoceptor transduction system

The effects of 1,2,3,4-tetrahydro-9-aminoacridine (THA) and physostigmine on ß-adrenoceptor-linked cyclic AMP accumulation have been analyzed in vitro in rat cortex and hippocampus. A 10-min incubation with increasing concentrations of THA reduced isoprenaline (10 μM)-stimulated cyclic AMP accumulation in a concentration-dependent manner in cortical (IC50 = 1.31 ± 0.13 μM) and hippocampal (IC50 = 0.02 ± 0.003 μM) structures. Conversely, physostigmine did not modify cyclic AMP synthesis in any experimental condition. The action of THA was non-competitive since it induced a non-parallel shift to the right of the concentration-response curve for isoprenaline. The differential effects of THA and physostigmine on the ß-adrenoceptor transduction system may account for the difference in their ability to restore cognitive function. © 1993.