The alpha 2-adrenoceptor antagonist, (+)-efaroxan, enhances acetylcholine release in the rat cortex in vivo.

Noradrenergic modulation of the cortical cholinergic system in vivo was studied by examining the effect of the selective alpha 2-adrenoceptor antagonist (+)-efaroxan on cortical acetylcholine outflow in the conscious rat, using the microdialysis technique. (+)-Efaroxan produced a dose-dependent increase in acetylcholine outflow (up to 300% at 0.63 mg/kg) which persisted for up to 3 h and which was stereospecific. The results demonstrate that rat cortical acetylcholine release can be augmented by (+)-efaroxan and that alpha 2-adrenoceptors may be involved. (+)-Efaroxan may have therapeutic potential in disorders in which cortical acetylcholine release is deficient.