The Effect of Thiamine Deficiency on the Acetylcoenzymea and Acetylcholine Levels in the Rat Brain

Abstract

Abstract— It is shown that transketolase activities in red blood cells and whole brain of normal and thiamine‐deficient rats correlate well with heart frequencies. The effect of thiamine depletion on the levels of acetylcoenzyme A (acetyl‐CoA) and acetylcholine (ACh), and on the activities of pyruvate dehydrogenase, choline acetyl‐transferase and acetylcholine esterase was studied in whole brains of thiamine‐deficient, thiamine‐supplemented ad libitum and pair‐fed rats. The concentrations of acetyl‐CoA and ACh decreased in thiamine‐deficient brains by 42 and 35 per cent, respectively. Total pyruvate dehydrogenase activity did not change during vitamin B1 deficiency. The ‘resolved’ enzyme, reconstituted with thiamine diphosphate, had an association constant of 5.4 × 10−6m. Choline acetyltransferase and acetylcholine esterase activities remained unchanged in thiamine deficiency. Possible mechanisms which could explain the reduced Ach levels in vitamin B1 deficiency are discussed.

Putative Significance of Shifts in Acetyl-CoA Compartmentalization in Nerve Terminals for Disturbances of Cholinergic Transmission in Brain

“…In addition, our data indicate that pyruvate oxidation and energy supply were of secondary importance for ACh production in depolarized cholinergic terminals when the acetyl-CoA transfer to the synaptoplasm was activated or uninhibited (tables 1-4). A direct assessment of subsynaptosomal compartmentalization of acetyl-CoA would appear to be necessary for an estimation of its involvement in the mechanism of cholinergic pathologies [23,24]. This statement is supported by the fact that for each effector used in this study, changes in calcium-evoked ACh release were correlated with shifts in the synaptoplasmic concentration of acetyl-CoA (r = 0.98; fig.…”

Impact of Exercise and Vitamin B₁ Intake on Hippocampal Brain-Derived Neurotrophic Factor and Spatial Memory Performance in a Rat Model of Stress

“…The resulting H2O2 reacts with a specifi c dye to form a pink-colored product. The color intensity at 570 nm is directly proportional to the Ach concentration in the sample (19).…”

Effects of early thiamin deficiency and subsequent rehabilitation on the cholinergic system in developing rat brain.

“…Thiamin deficiency, however, was not found to have any effect on activities of the cholinergic enzymes, acetylcholine esterase (AChE) and choline acetylase (ChAc), in the adult rat brain (17). There is no report of the study on the effects of early thiamin deficiency on the cholinergic system in the developing rat brain.…”

“…Heinrich et al also reported unaltered activities of the cholinergic enzymes in the symptomatic thiamin deficient rats (17).…”

“…Several studies have revealed that brain ACh levels are significantly lowered in thiamin deficiency induced by feeding thiamin deficient diet or by administration of thiamin antagonists to adult rats (15)(16)(17). Thiamin deficiency, however, was not found to have any effect on activities of the cholinergic enzymes, acetylcholine esterase (AChE) and choline acetylase (ChAc), in the adult rat brain (17).…”