Effects of CDP-choline treatment on neurobehavioral deficits after TBI and on hippocampal and neocortical acetylcholine release

The exogenous administration of cytidine-5'-diphosphate (CDP)-choline has been used extensively as a brain activator in different neurological disorders that are associated with memory deficits. A total of 50 rats were utilized to (a) determine whether exogenously administered CDP-choline could attenuate posttraumatic motor and spatial memory performance deficits and (b) determine whether intraperitoneal (i.p.) administration of CDP-choline increases acetylcholine (ACh) release in the dorsal hippocampus and neocortex. In the behavioral study, traumatic brain injury (TBI) was produced by lateral controlled cortical impact (2-mm deformation/6 m/sec) and administered CDP-choline (100 mg/kg) or saline daily for 18 days beginning 1 day postinjury. At 1 day postinjury, rats treated with CDP-choline 15 min prior to assessment performed significantly better than saline-treated rats. Between 14-18 days postinjury, CDP-choline-treated rats had significantly less cognitive (Morris water maze performance) deficits that injured saline-treated rats. CDP-choline treatment also attenuated the TBI-induced increased sensitivity to the memory-disrupting effects of scopolamine, a muscarinic antagonist. The microdialysis studies demonstrated for the first time that a single i.p. administration of CDP-choline can significantly increase extracellular levels of ACh in dorsal hippocampus and neocortex in normal, awake, freely moving rats. This article provides additional evidence that spatial memory performance deficits are, at least partially, associated with deficits in central cholinergic neurotransmission and that treatments that enhance ACh release in the chronic phase after TBI may attenuate cholinergic-dependent neurobehavioral deficits.