Is 2-dimethylaminoethanol (deanol) indeed a precursor of brain acetylcholine? A gas chromatographic evaluation

Acute administration of deanol-p-acetamidobenzoate (Deaner; deanol) has been reported to elevate brain choline (CH) and acetylcholine (ACh) levels. We have developed a specific and sensitive gas chromatographic assay to measure deanol levels in tissue and have applied this assay to our studies of the effect of acute deanol administration on deanol, ACh and Ch levels in rodent brains. Details of the method are described in this text. This procedure is quantitative and yields reproducible results over a wide range of deanol concentrations (0.30-200 nmol). Seven endogenous and pharmacological parameters have been studied using this procedure. In control rodent brain, liver, heart, lung and plasma, we detected no free endogenous deanol (less than 1 nmol/g). After deanol administration, we were able to detect deanol in tissue and have attempted to determine a relationship between these levels and values of ACh in the same tissue. Regardless of deanol pretreatment time (1-30 minutes) or doses (33.3-3000 mg/kg i.p.) used, we detected no increase in mouse whole brain ACh levels. Likewise, there was no detectable elevation in ACh levels in rat whole brain, cortex, striatum or hippocampus after a 15-minute pretreatment with 550 mg/kg of deanol (i.p.). The only elevation in ACh levels which we detected occurred selectively in the striatum of mice pretreated with a massive dose (900 mg/kg i.p.) of deanol for 30 minutes. This selective increase in striatal ACh levels oculd not, however, be related to levels of deanol in the striatum because there was no greater accumulation of deanol in the striatum than in other brain areas tested or in whole brain. These data do not confirm the results of other investigators who reported elevations in whole brain or striatal ACh levels after acute administration of lower doses of deanol. The data emphasize the need for further investigation into the mode of action of deanol and question its suggested role as an immediate precursor of ACh synthesis in the central nervous system.