Cholinergic ‘Blockade’ as a Model for Cholinergic Depletion

Abstract

The effect of cholinergic 'blockade' on human memory performance as a model for the effect of cholinergic depletion in clinical disorders was investigated. A wide range of memory functions was assessed in 70 subjects, using tests which were identical or closely similar to those which have previously been employed in clinical studies of Alzheimer and Korsakoff patients. In addition, a physiological measure of the degree of central cholinergic blockade was included, as well as measures of subjective arousal and objective attention. It was found that cholinergic blockade had no significant effect on the more passive aspects of primary (or 'working') memory, namely span tests and a measure of verbal short-term forgetting; in this, it contrasts with the marked deficits seen in Alzheimer-type dementia. On the other hand, cholinergic blockade produced impairment at a visuospatial short-term forgetting test, and at a verbal test in which the distractor task was made more difficult. On tests of secondary memory, cholinergic blockade produced a pattern similar to that seen in the anterograde amnesia of Alzheimer and Korsakoff patients, namely a pronounced impairment in learning verbal and visuospatial material, a 'normal' forgetting rate once learning had been accomplished, and relative preservation of the response to priming and of skill learning (procedural memory). Cholinergic blockade, however, did not produce a retrograde amnesia, nor did it affect the recall of temporal context or of long-established semantic knowledge. This pattern of results is compared with that obtained in previous studies of Alzheimer and Korsakoff patients.

Daidzein Activates Choline Acetyltransferase from MC-IXC Cells and Improves Drug-Induced Amnesia

“…Scopolamine, a muscarinic antagonist, impairs both learning and memory in rodents and humans, and particularly affects the processes of learning and short-term memory. 8,9) Hence it has been used in many previous studies in models for the screening of anti-amnesic drugs. In this study, amnesia was induced in mice via subcutaneous administrations of scopolamine (1 mg/kg body weight).…”

A Double FDG/PET Study of the Effects of Scopolamine in Older Adults

“…In the authors' experience, all subjects administered this dose experience cognitive impairment. The timing of the scans was based on prior studies showing that the am nestic effects of IV scopolamine occur to a consistent degree 60 to 150 minutes after administration (Sunder land et al 1987;Kopelman and Corn 1988;Molchan et al 1992).…”

Effect of Tremella fuciformis on the Neurite Outgrowth of PC12h Cells and the Improvement of Memory in Rats

“…Scopolamine is a muscarinic cholinergic receptor antagonist, and it impairs learning and memory in rodents and humans, and especially the process of learning, acquisition and short-term memory 28) ; scopolamine-induced amnesia has been used as a model for screening anti-amnesic drugs. 29) In this study, we examined the effect of a water extract of TF (0.01-1 mg/ml) on neurite outgrowth in PC12h cells. Since neuritogenesis plays an important role in regulating the process of learning and memory, we also investigated the memory-improving effects of TF in scopolamine-induced amnesic rats with using the Morris water maze test and choline acetyltransferase (ChAT) immunohistochemistry.…”