Acetylcholine Metabolism in Brain: Is it Reflected by CSF Changes? In: Fisher A, Hanin I, Lachman C, editors. Alzheimer’s and Parkinson’s Disease. Boston: Springer US; 1986. pp. 309-16. [DOI: 10.1007/978-1-4613-2179-8_37]

Brain and cerebrospinal fluid cholinesterases in Alzheimer's disease, Parkinson's disease and aging. A critical review of clinical and experimental studies

Acetylcholinesterase (AChE), an enzyme responsible for the break-down of acetylcholine, is found both in cholinergic and non-cholinergic neurons in the central nervous system. In addition to its role in the catabolism of acetylcholine, AChE have other functions in brain, e.g. in the processing of peptides and proteins, and in the modulation of dopaminergic neurons in the brain stem. Several clinical and experimental studies have investigated AChE in brain and cerebrospinal fluid (CSF) in aging and dementia. The results suggest that brain AChE and its molecular forms show interesting changes in dementia and aging. However, CSF-AChE activity is not a very reliable or sensitive marker of the integrity and function of cholinergic neurons in the basal forebrain complex. Additional work is needed to clarify the role of AChE abnormality in the formation of pathology changes in patients with Alzheimer's disease.

Monoamine metabolite concentrations and cholinesterase activities in cerebrospinal fluid of progressive dementia patients: relation to clinical parameters

Forty-five well clinically characterized patients with progressive dementia were investigated for lumbar cerebrospinal fluid (CSF) monoamine metabolites and cholinesterase activities. Monoamine concentrations were determined by reverse phase liquid chromatography with electrochemical detection and the cholinergic enzymes were measured photometrically. Firstly, all clinical and CSF parameters were studied in statistical cluster analyses to detect groups of variables which demonstrated a high correlation with respect to each other. The CSF transmitter markers were then used in multiple regression models to explain the variance of clinical variables as chosen from the cluster analyses. The degree of dementia, as assessed by global deterioration score (GDS) and activity in daily life (ADL) status, as well as the Alzheimer-related symptoms dyspraxia and dysphasia, were associated with low AChE activities in CSF. A presumed subgroup of dementia patients clinically characterized by asymmetry of neurological signs, increased unilateral tonus, stepwise progression, and high Hachinski score, showed low HVA concentrations in CSF. These data suggest a coupling of clinical/neurological parameters to different CSF transmitter profils and, thus, that CSF biochemical parameters are of use as antemortem markers in dementia conditions.

Increased monoamine metabolite concentrations and cholinesterase activities in cerebrospinal fluid of patients with acute stroke

Twenty-one patients with acute brain infarction, 8 with transient ischemic attack and 20 controls were investigated for lumbar cerebrospinal fluid (CSF) monoamine metabolites and cholinesterases. The diseased patients were lumbar punctured on 2 occasions, mean Days 1 (0-3) and 5 (3-9) after debut of symptoms. Monoamine concentrations were determined by reverse phase liquid chromatography with electrochemical detection and the cholinergic enzymes were measured photometrically. Increased concentrations of 3-methoxytyramine (3-MT), homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HI-AA) and increased activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in lumbar cerebrospinal fluid was found in patients with acute brain infarction when compared to control values, while the levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) were not altered. No change of any neurotransmitter metabolite concentration/enzyme activity were found between Day 1 and Day 5 in the diseased patients. These data suggest an increased release of these neurotransmitter markers from necrotic brain areas into the cerebrospinal fluid and/or altered barriers between blood, brain and CSF and/or a dysfunction of the arachnoid villi to clear substances from the CSF. We therefore concluded that CSF neurotransmitters may be useful as specific brain markers in acute stroke.

Release of acetylcholinesterase from the caudate nucleus of the rat

Acetylcholinesterase (AChE) can be released in the perfusate of rat caudate nucleus (CN) slices by two different modes of stimulation, with electrical stimulation at 5 Hz and with high concentrations of K+ (105 mM) using K+-propionate. We were unable to demonstrate AChE release with lower K+ concentrations (50 mM); however, at this concentration the drop in AChE activity seen in resting conditions was prevented. Practically all (95%) cholinesterase (ChE) found in the rat CN is AChE, which is represented by two major molecular forms (4S and 10S). In the perfusate, only AChE activity could be detected. A comparison of acetylcholine (ACh) and AChE release showed that maximal 3H-outflow and AChE release occurred at the same frequency (5 Hz), but the onset of AChE release was delayed. With high K+ (105 mM) depolarization, AChE release started after termination of the stimulation and continued for at least 50 min. These findings are consistent with the view that soluble form(s) of AChE can be slowly released from neurons under specific conditions of depolarization. In the caudate of the rat, the most likely sites for this release are processes of cholinergic interneurons. A hypothesis of AChE release is presented, and possible physiological and pathological implications of such a mechanism are discussed.