CO-DERGOCRINE (HYDERGINE) REGULATES STRIATAL AND HIPPOCAMPAL ACETYLCHOLINE-RELEASE THROUGH D(2) RECEPTORS

THE effect of Co-dergocrine (Hydergine) on acetylcholine (ACh) release in the striatum and hippocampus has been studied by means of brain mi crodialysis and compared to the effect of SKF 38393 and of LY 171555 s elective D1 and D2 dopamine (DA) receptor agonists, respectively. Co-d ergocrine (1 and 5 mg kg-1 i.p.) as well as LY 171555 (0.2 and 0.5 mg kg-1 i.p.) decreased the extracellular concentration of ACh in the str iatum, whereas SKF 38393 (5 and 10 mg kg-1 i.p.) increased it. On the other hand, Co-dergocrine (1 and 5 mg kg-1), LY 171555 (0.2 and 0.5 mg kg-1) and SKF 38393 (5 and 10 mg kg-1) increased ACh release in the h ippocampus in a dose-dependent way. These results show that Co-dergocr ine, which is widely used in the treatment of senile mental decline, e nhances the release of ACh in the hippocampus in a similar manner to b oth D1 and D2 DA agonists. This effect might be relevant for the ameli oration of cognitive processes. Moreover, our results which demonstrat e that Co-dergocrine is able to decrease the release of ACh in the str iatum, as are selective D2 agonists, suggest that Co-dergocrine may ha ve a potential therapeutic benefit in Parkinsonian dementia.