Pharmacological consequences of cholinergic plus serotonergic manipulations

The present study investigated pharmacological consequences of combined cholinergic and serotonergic blockade. Raphe medianus (RM) lesions (5,7-DHT) had no effect on spatial learning, but augmented scopolamine 0.8 mg/kg induced learning deficit. Pilocarpine (4 mg/kg) could reverse scopolamine (0.8 mg/kg), but not scopolamine (0.8 mg/kg) + RM lesion induced spatial learning impairment. However, a higher dose of pilocarpine could restore spatial learning deficit induced by scopolamine (0.8 mg/kg) and RM lesions. These findings support the important role of cholinergic-serotonergic interaction in the regulation of spatial learning and suggests that the combined cholinergic-serotonergic deficit in patient's with Alzheimer's disease may have an impact on therapeutic approaches which seek to normalize AD related cognitive impairments.