Scopolamine-induced deficits in spontaneous alternation performance: attenuation with lateral ventricle injections of glucose.

This experiment determined whether centrally administered glucose can attenuate scopolamine-induced deficits in spontaneous alternation performance. All rats were surgically prepared with indwelling cannulae directed at the lateral ventricle. Thirty min prior to alternation tests, rats received systemic (ip) injections of saline or scopolamine (3 mg/kg). Ten or thirty min prior to training, the rats also received a direct injection into the lateral ventricle of either artificial cerebrospinal fluid (CSF) or glucose (3 micrograms in 1 microliter). Scopolamine significantly impaired spontaneous alternation performance relative to controls. Additional treatment with ICV glucose 30 min, but not 10 min prior to testing, significantly attenuated the scopolamine-induced deficit. These results add support to the view that glucose acts directly on brain systems to attenuate behavioral effects of cholinergic antagonists.