Acetylcholinesterase and pseudocholinesterase activities in anxiety

Biochemical Analysis and Association of Butyrylcholinesterase SNPs rs3495 and rs1803274 with Substance Abuse Disorder

Addiction is a complex mental and behavioral disorder that changes the neurochemistry and physiology of the brain. Genetics also plays a significant role in the pathophysiology of addiction. Butyrylcholinesterase (BChE), a cholinergic enzyme, has been implicated in the metabolism of various drugs, including cocaine, and an association between single-nucleotide polymorphisms (SNPs) of the butyrylcholinesterase gene (BCHE) and neuronal disorders has been reported. We report here the first investigation to be conducted on the status of BChE activity and the potential association of two BCHE gene SNPs, rs3495 (c.*189G > A) and rs1803274 (c.1699G>A, p.Ala567Thr, K-variant), with addiction vulnerability in heroin, hashish and polydrug users. Seventy-five individuals with an addiction to heroin, hashish and/or polydrug use were recruited to this study. BChE levels in the plasma were determined by Ellman's principle. SNPs were genotyped by standard procedures, followed by Sanger sequencing. Plasma BChE levels were found to be significantly higher (p ≤ 0.05) in addicts (mean ± standard error of the mean 0.031 ± 0.004 μmol/L/min; 95% confidence interval [CI] 0.024-0.038) than in non-addicts (controls) (0.014 ± 0.001 μmol/L/min; 95% CI 0.012-0.017). Statistical significant differences were also observed between the addicted cohorts. A statistically significant association for both SNPs (rs3495 and rs1803274) was not observed in addicted subjects tested in the dominant, recessive and allele genetic models, but trends of variations of the rs3495 risk G allele were noted. The authors conclude that BChE plays significant roles in addiction pathophysiology as increased BChE activity in blood samples obtained from the cohorts with addiction was evident. Further studies in this direction may provide novel approaches for the treatment of addiction, but studies with a larger sample size and different ethnic groups are warranted for broader conclusions to be drawn.

Pseudocholinesterase levels in patients under electroconvulsive therapy

Objectives:

In this study, we aimed to retrospectively assess the correlation of pseudocholinesterase (PChE) levels with age, gender, body weight and diagnosed psychiatric diseases in electroconvulsive therapy (ECT) cases.

Methods:

This retrospective study was conducted at Bülent Ecevit University Hospital, Zonguldak, Turkey, between 2007 and 2011. In the study, 193 ECT case files were retrospectively scanned to evaluate PChE values before ECT and other file information.

Results:

There was no difference between gender in terms of PChE levels. Correlation analysis determined a weakly positive correlation between age (p=0.013; correlation coefficient [cc]: 0.178) and body weight (p<0.001; cc: 0.273) and PChE levels. No correlation was found between age, gender, weight or psychiatric diagnosis, and PChE levels.

Conclusion:

Neuromuscular blockage is a significant factor that increases patient safety, while increasing the efficacy of ECT. In choosing muscle relaxant agents, both patient factors and the pharmacological properties of the neuromuscular blocker should be considered. We think that in situations with delayed recovery of ECT cases without identified PChE levels, low PChE levels must be considered.

Pseudocholinesterase activity increases and heart rate variability decreases with preoperative anxiety

BACKGROUND AND OBJECTIVE

The objective of this study was to determine the influence of preoperative anxiety on the activity of plasma cholinesterase and heart rate (HR) variability.

METHODS

A total of 50 subjects were studied, 25 male patients one day preoperatively and 25 male volunteers without surgical intervention as a control group. Blood samples were taken to determine plasma cholinesterase activity. HR variability was recorded for a period of 256 beat-to-beat intervals and analysed by frequency domain analysis into very low frequency (VLF: 0.02-0.04 Hz), low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.4 Hz). LF/HF ratio and total power over the 0.02-0.4 Hz range were calculated. Anxiety levels were assessed using the hospital anxiety and depression scale, the self-rating anxiety scale and a visual analogue scale.

RESULTS

The patient group had significantly higher anxiety scores. Plasma cholinesterase activity was significantly higher in patients vs. controls (6646 vs. 5324 units L(-1)). Total power, LF and HF were significantly lower in the patients (1489 vs. 2581 ms2; 656 vs. 1186 ms2; 491 vs. 964 ms2, respectively).

CONCLUSIONS

Preoperative anxiety increases plasma cholinesterase activity and decreases HR variability.

Serum cholinesterase in obsessive-compulsive disorder

Levels of serum cholinesterase (PsChe) were measured in 32 drug-free patients with obsessive-compulsive disorder (OCD) and 32 sex- and age-matched healthy normal volunteers. No significant differences between OCD patients and normal subjects were found in PsChe levels. A significant positive correlation between patients' PsChe levels and the severity of anxiety, as measured by the Hamilton Rating Scale for Anxiety, was found, in agreement with the hypothesis of a relationship between state anxiety and PsChe activity. In contrast to findings in other reports, PsChe levels significantly increased after 10 weeks of antiobsessional pharmacological treatment, underscoring the potential influence of drugs on PsChe activity.

Pseudocholinesterase in obsessive-compulsive patients

Levels of pseudocholinesterase (PsChe) were measured in 20 patients with obsessive-compulsive disorder (OCD) and 20 healthy volunteers. The OCD group had significantly higher PsChe serum activity than in their sex- and age-matched control group. Patients' scores on the Hamilton Rating Scale for Anxiety (HRS-A) and the Beck Depression Inventory (BDI) were not correlated with their PsChe levels. The results provide additional support for the observation of higher PsChe levels among anxiety-related psychiatric conditions. However, the relationships among anxiety, depression, and PsChe appear to be complex. The nature and implications of elevated PsChe levels are still unknown.

Systemic hormonal and physiological abnormalities in anxiety disorders

Among the studies of systemic hormonal and physiological abnormalities associated with anxiety disorders, the most consistent and extensive findings suggest (a) peripheral adrenergic hyperactivity (including increases in norepinephrine but not epinephrine) and functional dysregulation, (b) increased incidence of mitral valve prolapse in panic patients, and (c) normal suppressibility of the hypothalamic-pituitary-adrenal cortical endocrine system with dexamethasone in panic patients. Other less-certain findings include (a) increased circulating concentrations of plasma ACTH and/or cortisol, and prolactin, in panic patients, (b) increased platelet monoamine oxidase activity in generalized anxiety and/or panic patients, (c) decreased gonadal axis activity in some anxious individuals, (d) decreased nighttime melatonin plasma concentrations in panic patients, and (e) peripheral alpha 2 and beta-adrenoreceptor down-regulation, with normal serotonin binding parameters. These findings, taken together, provide tentative support for dysfunction in adrenergic and GABAergic central nervous system mechanisms in people with anxiety disorders. Abnormal anxiety and normal stress both show evidence of adrenergic hyperactivity; however, there appear to be differences in hormonal profiles, especially the apparent lack of increase of epinephrine during panic attacks, as well as differences in the reactivity of the system, and in the "trigger" mechanisms which determine when the response occurs.

Serum pseudocholinesterase in psychiatric patients

Serum pseudocholinesterase activity was measured in 123 subjects: 16 agitated depressives, 12 retarded depressives, 7 acute schizophrenics, 14 residual schizophrenics, 16 healthy individuals, 45 surgical patients, and 13 first-degree relatives of 4 agitated depressive patients. The agitated depressive and acute schizophrenic patients had significantly higher pseudocholinesterase serum activity than their retarded inmates. As first-degree relatives of agitated depressive patients showed high levels similar to their ill relatives, a genetic component might play a crucial role. The level of pseudocholinesterase activity in serum of the surgical patients was significantly lower than that of all the psychiatric patients and the controls. The implications of this observation are still obscure.

Molecular forms of acetylcholinesterase and butyrylcholinesterase in human plasma and cerebrospinal fluid

The measurement of cholinesterase activities in either plasma or cerebrospinal fluid (CSF) may ultimately prove to be relevant in the diagnosis of neurological and neuropsychiatric disorders. However, studies to date have examined only total enzyme activities. Therefore in the present study we have examined the distribution of the individual molecular forms of both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in plasma and CSF using sucrose density gradient centrifugation. Although the total activities of AChE were of the same order of magnitude in plasma and CSF, there was a considerable difference (120-500-fold) between total BChE activity in the CSF and the BChE-rich plasma. The analysis of the individual molecular forms revealed that the predominant molecular species of AChE and BChE in the CSF--both lumbar and ventricular--was the G4 form. The G4 form also constituted the majority of the plasma BChE activity and, on average, over half (56%) of the plasma AChE activity. The significance of the AChE and BChE molecular form compositions of both plasma and CSF and their possible relationship to pathological states are discussed.

Blood acetyl- and butyrylcholinesterases in senile dementia of Alzheimer type

The major neurochemical abnormality described to date in senile dementia of the Alzheimer type (SDAT) is a central cholinergic deficit. To determine whether this central deficit is reflected by changes in the levels of blood cholinesterases, plasma and erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE), were measured in SDAT and other psychiatric disorders. Plasma AChE, which has only recently been described in human blood, was significantly elevated (P less than 0.01) in the SDAT group compared with the control and other clinical groups investigated. In contrast there were no significant differences in the activities of either erythrocyte AChE or plasma BChE between any of the clinical groups. Although the source of plasma AChE is unknown the possibility that some portion originates from the central nervous system and that the elevated AChE levels in SDAT reflect increased release from degenerating cholinergic neurons is discussed.

Cholinesterase enzymes in the blood of patients with Alzheimer's disease

Plasma pseudocholinesterase activity was about 100% higher in patients with Alzheimer's type dementia than in similar age controls. Red cell acetylcholinesterase activity tended to be lower in patients than controls. Administration of lecithin substantially increased plasma choline levels but did not alter activity of either of the cholinesterase enzymes.