Stimulatory and inhibitory effects of ethanol on hippocampal acetylcholine release

Abstract

Using the microdialysis technique and sensitive HPLC procedures for the determination of acetylcholine (ACh) and ethanol, we investigated the release of ACh in rat hippocampus after acute ethanol administration. Systemic administration of ethanol (0.8 and 2.4 g/kg i.p.) led to peak ethanol concentrations of 21 and 42 mM in the hippocampus, respectively. The high dose caused a long-lasting inhibition of basal ACh release by up to 33%. Local infusion of scopolamine (1 microM) enhanced hippocampal ACh release up to eightfold in the presence of neostigmine (10 microM), and this stimulated release was also inhibited after systemic ethanol administration (by up to 45%). The low dose of ethanol (0.8 g/kg) led to a delayed stimulation of hippocampal ACh release. A stimulatory effect on ACh release was also observed when ethanol (50-100 mM) was infused directly into the hippocampus or into the septal area, i.e. to the origin of the cholinergic septohippocampal pathway; thus, the stimulatory effect may be mediated by a direct effect on cholinergic fibres. We conclude that ethanol exerts dual modulatory effects on the activity of the septohippocampal cholinergic fibres, depending on the dose and the site of administration. It is suggested that the inhibition of hippocampal ACh release by intoxicating doses of ethanol may contribute to the well-known cognitive and amnesic effects of ethanol intake.

Wine consumption, cognitive function and dementias – A relationship?

“…In a rat model, a moderate concentration of ethanol (0.8 g/kg) stimulated the release of acetylcholine while a higher concentration (2.4 g/kg) inhibited its release [115]. The formation of amyloid fibrillar plaques is also common in diseases such as Parkinson's disease, prion diseases, Down's syndrome and type II diabetes [116][117][118][119][120][121].…”

“…Alcohol acts directly and indirectly on the central nervous system [14,16,115] and alcohol abuse causes cognitive impairment.…”

Effects of Melissa officinalis on ethanol state-dependent learning in nicotine- treated mice

“…The present results also show that, the pretrain and pre-test administration of ethanol also reversed the decrease in inhibitory avoidance response induced by ethanol. Studies suggested that the inhibition of hippocampal ACh release by intoxicating doses of ethanol may contribute to the wellknown cognitive and amnesic effects of ethanol intake [29]. Acute ethanol administration produces dose-dependent impairments in spatial learning.…”

Is there a role for wine in cancer and the degenerative diseases of aging?

“…175 In a rat model, a moderate concentration of alcohol (0.8 g/kg) stimulated the release of acetylcholine while a higher concentration (2.4 g/kg) inhibited its release. 176 Four studies have further suggested that moderate wine consumption is associated with a lower risk of dementia and specifically Alzheimer's disease. [176][177][178][179][180][181] In the prospective population-based study by Orgogozo and colleagues 176 the sole source of alcohol was wine for 95% of consumers, which did not allow for beverage differentiation.…”

“…176 Four studies have further suggested that moderate wine consumption is associated with a lower risk of dementia and specifically Alzheimer's disease. [176][177][178][179][180][181] In the prospective population-based study by Orgogozo and colleagues 176 the sole source of alcohol was wine for 95% of consumers, which did not allow for beverage differentiation. In the Copenhagen City Heart Study (1991−1994) and in the Washington Heights InwoodColumbia Aging Project (1991−1996), however, only wine was associated with a lower risk or incidence.…”