Differences in platelet enzyme activity between alcoholics and nonalcoholics

Relationship between alcohol consumption and the activity of GTP-binding regulatory proteins in human erythrocyte membranes

Activity of stimulatory GTP-binding regulatory protein (Gs) in human erythrocyte membranes was assessed by activation of adenylate cyclase in S49 murine lymphoma variant cells to elucidate a relationship to alcohol consumption. In apparently healthy subjects, alcohol consumption < 50 g ethanol per week did not alter the Gs activity, but it was significantly higher (14.3%, P < 0.05) in moderate drinkers (50-150 g/week) than non-drinkers. Then, the Gs activity declined with a further increase in alcohol consumption (150-550 g/week). Those subjects with drinking levels of > 50 g/week also showed significant increases in other alcohol-related markers, Na+, K(+)-ATPase and gamma-glutamyltransferase. The Gs activity was significantly low in alcoholics (a 34.9% reduction). No such reduction was noted in patients with other diseases. The results indicate that the Gs activity in erythrocyte membranes is an alcohol-related marker in humans. The variation of Gs activity is distinctive from those of other alcohol-related markers.

Enhanced expression of the inhibitory protein Gi2 alpha and decreased activity of adenylyl cyclase in lymphocytes of abstinent alcoholics

Ethanol exposure alters signal transduction through the adenylyl cyclase (AC) system. To elucidate the basis for this effect, we investigated the AC system in peripheral lymphocytes from abstinent alcoholic men (n = 22), actively drinking alcoholic men (n = 41), and nonalcoholic control men (n = 16). Immunoblot analysis of lymphocyte membranes from abstinent alcoholics demonstrated a 3.0-fold increase in the level of Gi2 alpha protein (p < 0.05) compared with controls. However, levels of Gs alpha protein were similar in both groups. Abstinent alcoholics had a 2.9-fold increase in Gi2 alpha mRNA (p < 0.001) and a 2.7-fold increase in Gs alpha mRNA (p < 0.03) compared with lymphocytes from control subjects. Actively drinking alcoholics, in contrast, had unaltered Gs alpha protein, Gi2 alpha protein, and Gi2 alpha mRNA levels compared with control subjects, but did have a 1.8-fold increase (p < 0.01) in Gs alpha mRNA. Consistent with enhanced Gi2 alpha expression, lymphocyte membranes from abstinent alcoholics had decreased basal, prostaglandin E1-, guanosine 5'-0-(3-thiotriphosphate)-gamma S-, and forskolin-stimulated AC activity compared with both controls and actively drinking alcoholics (p < 0.05). We conclude that lymphocyte AC is reduced during abstinence from alcohol and enhanced expression of the inhibitory G-protein, Gi2 alpha, may account for this change.

Why there is no gene for alcoholism

The search for and recognition of biological and genetic markers of alcoholism are discussed in the context of a heuristic model of human alcoholism as a complex, multilocus, heterogeneous disorder. Implications of this model for the interpretation of results from both linkage and association studies are presented.

Relationship between platelet monoamine oxidase B activity and alleles at the MAOB locus

Genetic variations in monoamine oxidase (MAO)-B activity have been proposed to have a contributory role in several neurologic and psychiatric diseases. Variations in activity could affect rates of degradation of exogenous amines, including toxins, precursors of toxins (like 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), or false transmitters, and of endogenous amines, such as neurotransmitters. In this study a highly polymorphic (GT)n repeat element was used to mark alleles at the MAOB locus. The MAOB allele status and levels of platelet MAO-B activity were determined for 41 control males. No correlation was noted between specific alleles and levels of MAO-B activity in this sample set. This suggests that the structural gene for MAOB is not usually the primary determinant of activity levels in platelets.

Low platelet gamma-aminobutyrate aminotransferase and monoamine oxidase activities in chronic alcoholic patients

The activities of gamma-aminobutyrate aminotransferase (GABA-T) and monoamine oxidase (MAO) were estimated in blood platelets from 25 male chronic alcoholics and from 27 healthy male volunteers without histories of alcohol abuse. Based on clinical criteria, the alcoholics were classified into type 1 or type 2 alcoholism. The activity of GABA-T was found to be lower both in type 1 and type 2 alcoholics than in healthy volunteers. With regard to MAO, the platelet activity was found to be significantly lower only in type 2 alcoholics in concordance with previous reports. No significant correlation was found between the activities of GABA-T and MAO in the blood platelets of healthy volunteers. The inhibitory effect of 400 mM ethanol on the platelet MAO activity increased with decreasing concentrations of the substrate phenylethylamine. The degree of inhibition of ethanol on the platelet MAO activity, however, did not differ significantly between alcoholics and controls.

Ethanol-responsive gene expression in neural cell cultures

We have studied the molecular mechanisms underlying neuronal adaptation to chronic ethanol exposure. NG108-15 neuroblastoma cells were used to perform a detailed analysis of ethanol-induced changes in neuronal gene expression. High resolution, quantitative two-dimensional (2-D) gel electrophoresis of in vitro translation products showed both dose-dependent increases and decreases in specific mRNA abundance following treatment with ethanol at concentrations seen in actively drinking alcoholics (50-200 mM). Dose response curves for representative members of the increasing or decreasing response groups had very similar profiles, suggesting that similar mechanisms may regulate members of a response group. Some mRNAs that increased with ethanol treatment appeared identical to species induced by heat shock while other mRNAs were only induced by ethanol. We conclude that chronic ethanol exposure can produce specific coordinate changes in expression of neuronal mRNAs, including some members of the stress protein response. However, the overall pattern of ethanol-responsive gene expression is distinct from the classical heat shock subgroup of stress proteins response. Changes in gene expression and specifically, mechanisms regulating a subset of stress protein expression, could be an important aspect of neuronal adaptation to chronic ethanol seen in alcoholics.

Ethanol exposure results in a transient decrease in human platelet cAMP levels: evidence for a protein kinase C mediated process

At concentrations between 2 and 32 mM, ethanol is shown to depress human platelet cAMP levels. The effect is biphasic, maximal at 30 sec, with platelet concentrations of cAMP returning to baseline values at higher ethanol concentrations and at longer incubation times. The cAMP lowering effect of ethanol can be blocked by a phosphodiesterase (PPDE) inhibitor, 3-isobutyl-1-methyl-xanthine (IBMX), at a concentration of 2 mM, suggesting that an increase in PPDE activity may be responsible for this effect. Exposure of platelets to 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), a protein kinase C (PKC) inhibitor, blocks the ethanol-induced decrease in platelet cAMP, suggesting ethanol may be acting through activation of PKC.

Biological markers of alcoholism

The roles of two categories of biological markers--those relating to alcohol consumption and those relating to the risk of developing alcohol related problems--are reviewed. Platelet Mono-amino oxidase levels are low in individuals with a strong inheritance of their drinking problem (Cloninger Type II alcoholics). Elevated gamma-glutamyl transpeptidase (GGT) levels identify regular heavy drinkers with a sensitivity between 40-60%. Mean corpuscular volume (MCV) has a high specificity (95%) and is useful in detecting regular heavy drinkers in the ambulatory care population if other causes of an elevated MCV can be included.

Why alcoholism is a disease

OBJECTIVE

To present the evidence that alcoholism is a disease.

SUMMARY

Most specialists have been led by their clinical experience to believe that alcoholism is a disease and it is classified as such in ICD-9 and DSM-III-R. Alcoholism has both biological and psychological elements. The relapse into alcoholism after extended abstinence and the inability of alcoholics to learn harmless social drinking indicate the tenacity of the disease. Genetic research suggests that there are inherited biological factors in alcoholism. Biological markers have been identified which differentiate alcoholics from other people.

CONCLUSION

While alcoholics are responsible for their decisions, they are not responsible for their biological predisposition to an abnormal response to alcohol.

Effects of chronic ethanol exposure on cardiac receptor-adenylyl cyclase coupling: studies in cultured embryonic chick myocytes and ethanol fed rats

Ethanol effects in the brain appear to be mediated at least in part by an alteration in receptor-effector coupling via guanine nucleotide-binding regulatory proteins (G proteins). To test the hypothesis that a similar pathway participates in the cardiotoxic effects of ethanol, we assessed the effects of chronic ethanol on two commonly used experimental models: embryonic chick myocytes in culture and ventricular myocardium from chronically fed rats. Ethanol had no effect on either the function or quantity of G proteins as assessed by effector-stimulated adenylyl cyclase activity and the levels of ADP-ribosylation substrates. In contrast, effector-stimulated adenylyl cyclase activity was significantly altered in the liver of ethanol-fed rats. These results suggest that receptor-effector coupling via G proteins in our two cardiac models is insensitive to ethanol and that ethanol effects may be species or organ specific.

Structure of the human gene for monoamine oxidase type A

Monoamine oxidases, type A and type B, are principal enzymes for the degradation of biogenic amines, including catecholamines and serotonin. These isozymes have been implicated in neuropsychiatric disorders. Previously, cDNA clones for both MAO-A and MAO-B have been sequenced and the genes encoding them have been localized to human chromosome Xp11.23-Xp11.4. In this work, we isolated human genomic clones spanning almost all the MAOA gene from cosmid and phage libraries using a cDNA probe for MAO-A. Restriction mapping and sequencing show that the human MAOA gene extends over 70 kb and is composed of 15 exons. The exon structure of human MAOA is similar to that described by others for human MAOB. Exon 12 (bearing the codon for cysteine, which carries the covalently bound FAD cofactor) and exon 13 are highly conserved between human MAOA and MAOB genes (92% at the amino acid level). Earlier work revealed two species of MAO-A mRNA, 2.1 kb and 4.5-5.5 kb. We now report on further cDNA isolation and sequencing, which demonstrates that the longer message has an extension of 2.2 kb in the 3' noncoding region. This extended region is contained entirely within exon 15. The two messages therefore appear to be generated by the use of two alternative polyadenylation sites. Results from the present work should facilitate the mutational analysis of functional domains of MAO-A and MAO-B. Knowledge of the gene structure will also help in evaluating the role of genetic variations in MAO-A in human disease through the use of genomic DNA, which is more accessible than the RNA, as a template for PCR-amplification and sequencing.

Hormonal tolerance to ethanol is associated with decreased expression of the GTP-binding protein, Gs alpha, and adenylyl cyclase activity in ethanol-treated LS mice

Using the proopiomelanocortin (POMC) system as a marker, long sleep (LS) and short sleep (SS) lines of mice were investigated to explore the cellular events that occur during the acquisition of hormonal tolerance to ethanol. Four-day ethanol exposure (1.8 g/kg/24 hr) increased anterior pituitary POMC mRNA levels 4-fold in the LS line and 2-fold in the SS line. Following 7 days of ethanol exposure (1.8 g/kg/24 hr), anterior pituitary POMC levels returned to basal values in the LS line but remained elevated (2-fold) in the SS line. In this setting, the loss of ethanol's ability to sustain elevated POMC mRNA levels in the LS line is defined as hormonal tolerance. Since POMC biosynthesis is primarily regulated through adenylyl cyclase, ethanol-induced alterations in this signal transduction system were explored. Paralleling the effects of ethanol on POMC mRNA levels, ethanol exposure reduced GTP-gamma-S, AIF3-, and MnCl2-stimulated adenylyl cyclase activity by 35%, 21%, and 24%, respectively, in the LS line without effecting adenylyl cyclase activity in the SS line. To determine whether ethanol-induced changes in adenylyl cyclase activity in LS mice could result from alterations in G proteins, protein levels of G, alpha and Gi alpha were determined by western analysis before and after ethanol exposure. Paralleling the effect on POMC mRNA levels and adenylyl cyclase activity, ethanol induced a 35% reduction in Gs alpha protein levels in LS mice but did not alter Gi alpha levels. Neither Gs alpha nor Gi alpha levels were altered in the SS line.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohols synergize with NGF to induce early differentiation of PC12 cells

The role of alcohols in affecting neuromorphogenesis was investigated in a single cell type, pheochromocytoma (PC12). The effect of ethanol at physiological concentrations in this system leads to enhanced morphological and functional differentiation in combination with nerve growth factor (NGF). PC12 cells treated with a suboptimal concentration of NGF (30 ng/ml) and an alcohol (87 mM) underwent rapid morphological differentiation which was dependent upon the side chain length of the alcohol MeOH less than EtOH less than PrOH less than BuOH. Pyrazole at either 5 or 10 mM had no effect on alcohol induced neurite extension. Assessment of the degree of differentiation promoted by the various alcohols was quantified by an increase in neurite extension, a decrease in the incorporation of [3H]thymidine, an increase in acetylcholine esterase (AChE) activity and immunostaining with neuron specific enolase. Thus, alcohols may function in a specific manner by interacting with transmembrane signalling pathways which promote gene expression and neuronal differentiation.

G proteins coupled to phospholipase C: molecular targets of long-term ethanol exposure

Long-term ethanol exposure is known to inhibit bradykinin-stimulated phosphoinositide hydrolysis in cultures of neuroblastoma x glioma 108-15 cells. In the present study, [3H]bradykinin binding, GTP-binding protein function, and phospholipase C activity were assayed in cells grown for 4 days in 100 mM ethanol with the aim of elucidating the molecular target of ethanol on signal transduction coupled to inositol trisphosphate and diacylglycerol formation. Ethanol exposure reduced guanosine 5'-O-(3-thiotriphosphate) [GTP(S)]- and, to a lesser extent, NaF/AlCl3-stimulated phosphoinositide hydrolysis, whereas it had no effect on the enzymatic activity of a phosphatidylinositol 4,5-bisphosphate-specific phospholipase C. [3H]Bradykinin binding in the absence of GTP(S) was not influenced by ethanol exposure. However, the reduction in [3H]bradykinin binding seen in control cells after addition of GTP analogue was inhibited in cells grown in ethanol-containing medium. The results indicate that long-term ethanol exposure exerts its effects on receptor-stimulated phosphoinositide hydrolysis primarily at the level of the GTP-binding protein.

Neuroadaptive responses to chronic ethanol

Cellular responses of neuronal tissue to chronic ethanol exposure are reviewed. Evidence for adaptive responses to the acute actions of ethanol is available for five systems: GABA-activated chloride channels, voltage-sensitive calcium channels, NMDA-activated cation channels, receptors coupled through stimulatory guanine nucleotide binding proteins, and membrane lipid order. We suggest that at least some of these adaptive responses occur because of ethanol actions at the level of gene expression.

Erythrocyte membrane characteristics indicate abnormal cellular aging in patients with Alzheimer's disease

Erythrocytes from patients with Alzheimer's disease show signs of disturbance of the normal cellular aging process. Immunoblotting of erythrocyte membrane proteins from Alzheimer patients reveals increased breakdown of the anion transport protein band 3 in a majority of the cells, similar to what is observed in only a very small cell population during normal aging. These structural changes are accompanied by changes in anion transport characteristics, but the latter partially deviate from those observed during normal aging. The amount of erythrocyte-bound immunoglobulin G, the most direct and relevant parameter of erythrocyte aging, is significantly increased in Alzheimer patients relative to age-matched, healthy donors and to patients with multi-infarct dementia. These data indicate accelerated molecular breakdown of band 3 and premature appearance of senescent cell characteristics in erythrocytes from Alzheimer patients, and support the hypothesis that abnormal cellular aging may be involved in the etiology of the Alzheimer-specific pathology.

Effects of ethanol on cAMP production in murine embryonic palate mesenchymal cells

Ethanol affected the ability of murine embryonic palate mesenchymal (MEPM) cells to produce cAMP in response to hormone treatment. Acute exposure to ethanol resulted in an increase in hormone-stimulated cAMP levels, while chronic ethanol treatment led to decreased sensitivity to hormone. Forskolin-stimulated cAMP levels were decreased by both acute and chronic ethanol treatment, while the cells' response to cholera toxin was unchanged by ethanol treatment. The lack of sensitivity of the cholera toxin response to ethanol suggests that, in contrast to what has been observed in other systems, ethanol does not affect the production or activity of G alpha s in MEPM cells. These results suggest a possible explanation for the molecular basis for the craniofacial abnormalities observed in the fetal alcohol syndrome.

Identifying genes determining trait differences in behavior and drug response: a comment on 'Quantitative trait loci and psychopharmacology'

In Plomin, McClearn and Gora-Maslak's target article (see also Science 248: 183-188, 1990), reverse genetic approaches are emphasized for locating genes determining behavioral and pharmacogenetic traits. Furthermore, prospects for such an undertaking are presented pessimistically in that behavioral traits are asserted to be polygenic (due to the simultaneous action of variant alleles at multiple loci) and are conceptualized as being determined in large part by unshared environmental factors. We disagree with Plomin et al. in three major areas and argue the following:(1) Forward genetic approaches involving candidate locus analysis and detailed analysis of the phenotype are of primary importance for isolating genes for behavioral traits, as for other genetic traits.(2) Virtually all physiologic processes and metabolic pathways involve sets of genes, resulting in genetic heterogeneity (multiple genetic origins for a trait). However, polygenicity is approximately as unusual for behavioral traits as for other traits.(3) Heritability analyses underestimate the extent to which behavioral traits are amenable to genetic analysis and have been misinterpreted to overestimate the importance of environmental factors.

Biological markers of alcoholism

Biological markers are biochemical or physiological characteristics which may help to classify a person according to the presence or absence of some disease or risk of disease, either with respect to their current status or future susceptibility. Many biological markers related to alcoholism have been described; this review suggests a classification of them and indicates areas where they are well-established and other areas where further investigation may be useful.

A comparative blinded study in miniature swine of whole blood-, hemoglobin-, platelet-, plasma-, and lymphocyte-associated acetaldehyde as markers for ethanol intake

Blood samples were obtained from miniature swine maintained on 0, 2, or 6 g/kg/24 hr ethanol for 8 months (N = 6 in each group). Samples from drinking pigs were taken after 8 hr of ethanol abstinence and all were coded and sent for "blinded" analysis. A fluorigenic high performance liquid chromatographic assay was used to quantify whole blood-associated acetaldehyde, hemoglobin-associated acetaldehyde, plasma-associated acetaldehyde, platelet-associated acetaldehyde, and lymphocyte-associated acetaldehyde. Detectable levels of acetaldehyde were found in each sample in both drinking and nondrinking pigs. Analysis of whole blood-associated acetaldehyde was most discriminatory in distinguishing nondrinking from drinking pigs (mean 21.4 +/- 1.0 microM for nondrinkers vs. 24.6 +/- 1.5 SD for the group consuming 2 g/kg ethanol, p = 0.001). Measurements of hemoglobin-associated acetaldehyde normalized to protein concentration (250 +/- 47 nmoles/g vs. 203 +/- 33 SD, p less than 0.05 drinking vs. nondrinking pigs) and platelet-associated acetaldehyde (0.46 0.34 vs. 0.15 +/- 0.16 nmoles/3 x 10(8) platelets, p = 0.05 drinking vs. nondrinking pigs) were also useful in discriminating drinking from nondrinking animals. Analysis of plasma-associated acetaldehyde and lymphocyte-associated acetaldehyde were not useful as markers of ethanol consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma beta-endorphin levels in chronic alcoholics

In order to test the possible relationship between the chronic consumption of alcohol and the opioid system, we have measured the plasma levels of beta-endorphin in a group of 31 alcoholic patients and compared the results with those of a control group of 16 subjects. Our results show that chronic consumption of alcohol induces a significant decrease in beta-endorphin (beta-end) plasma levels regardless of either the disease suffered by the alcoholic patient or of the time of abstinence studied (one month maximum). Thus we believe that the beta-end decrease may well be due to the patients' alcoholism and that it might be mediated by the tetrahydroisoquinoline system, or be a cause of alcoholism rather than a consequence.

Direct effects of chronic ethanol exposure on beta-adrenergic and adenosine-sensitive adenylate cyclase activities and cyclic AMP content in primary cerebellar cultures

The direct effects of chronic ethanol exposure on adenylate cyclase activity and cyclic AMP content were investigated in primary cerebellar cultures. By morphological criteria these cultures mainly contain granule cells with some astrocytes, and each cell type appears to contain both beta-adrenergic and adenosine-sensitive adenylate cyclase systems. Chronic treatment of the primary cerebellar cultures with 120 mM ethanol for 6 days caused a reduction in the stimulation of cyclic AMP content by isoproterenol and by the adenosine analogue 2-chloroadenosine. Kinetic analysis indicated that the chronic ethanol treatment decreased maximal activation of adenylate cyclase, as well as increased the EC50 values for norepinephrine and 2-chloroadenosine. Activation of norepinephrine-stimulated adenylate cyclase activity by in vitro ethanol was significantly enhanced after the chronic ethanol exposure. However, the chronic treatment did not alter activation of the 2-chloroadenosine-stimulated enzyme by in vitro ethanol. A similar difference in the response to in vitro ethanol after the chronic treatment was observed when cyclic AMP content of the intact cells was measured. The present data indicate that chronic ethanol exposure causes a selective increase in the sensitivity of adenylate cyclase to ethanol in some brain cells and a more generalized desensitization of receptor-stimulated cyclic AMP production.

Platelet MAO in subtypes of alcoholism

A number of investigators have observed low platelet monoamine oxidase (MAO) activity in alcoholism. There is also preliminary evidence suggesting that low enzyme activity is principally associated with one of two putative subtypes of alcohol dependence, i.e., type II (male limited). The results of this study are consistent with two previous reports of reduced platelet MAO activity in type II male alcoholics as compared with type I male alcoholics and normal, healthy male controls. Type I (milieu-limited) alcoholics showed a smaller reduction in enzyme activity. The observed differences do not appear to be related to concurrent use of other psychoactive substances, characteristic differences in age between type I alcoholics and type II alcoholics, antisocial personality disorder, or variation in platelet size. Low platelet MAO activity in alcoholics is possibly related to both state and trait factors and may be a useful biochemical measure to assist with subtyping.

The effect of ethanol on platelet function and vascular prostanoids

The present review will discuss the effects of ethanol on platelet function and vascular prostanoids. Whenever possible we have considered human studies because there are marked species differences in platelet function and vascular prostanoid release even in the absence of ethanol. Because of the specialised nature of some parts of the text, we have included brief introductions to help readers who are not familiar with this field.

Biochemistry and genetics of monoamine oxidase

This chapter reviews the two mitochondrial flavin containing isozymes of monoamine oxidase. Section 1, "Biochemistry" discusses assays, substrates and inhibitors, phylogenic and tissue distribution, interactions with lipids, nutritional studies, protein structure, kinetic and chemical mechanistic proposals, and biosynthesis. Section 2, "Inheritance" discusses possible genes involved in expression, genetic studies of platelet MAO-B and fibroblast MAO-A, and chromosomal location. Section 3, "Molecular Genetics" reviews the cloning of their cDNAs, their intra- and interspecies homology and structural inferences made from deduced amino acid sequences. Section 4, "Regulation" gives an overview of levels in development and aging, and effect of drugs. The final section 5, "Role in Human Disease" discusses physiological function and effects of altered levels in humans and animal models including complete absence due to a submicroscopic chromosomal deletion in several human patients.

The genetics of human alcohol metabolism

1. The custom of drinking alcoholic beverages is a human behavior with serious social and medical consequences for a surprisingly large fraction of drinkers. 2. This review describes recent advances in our understanding of the genetic loci that control enzyme systems involved in the metabolism of alcohol. 3. These advances make possible new experimental programs that may lead to simple diagnostic tests for patients at risk of developing alcohol abuse behaviour.

Catchers in the rye

There is a great need for more research in child and adolescent psychiatry, and this must be clinically, as well as laboratory, based. There are, however, much data already available on alcohol and handguns that, if used, could substantially decrease morbidity and mortality rates for adolescents.

Platelet responses to platelet-activating factor are inhibited in alcoholics undergoing alcohol withdrawal

Platelet aggregation, secretion of serotonin, and formation of thromboxane B2 induced by platelet-activating factor (1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine) were studied in plasma containing physiological concentrations of ionized calcium in eight alcoholics after cessation of heavy drinking. Responses of platelets of four nonalcoholic volunteers, matched with a subgroup of the alcoholics by age and sex, were also investigated. Aggregation of platelets from alcoholics was significantly less throughout the 6-day detoxification period compared with controls. Secretion of serotonin (5-hydroxy-tryptamine) was negligible and the production of thromboxane B2 was not detectable. Decreased platelet aggregability in response to aggregating agents, including platelet-activating factor, may be important in the development of hemorrhagic complications in alcoholics.

An analysis of postmortem brain samples from 32 alcoholic and nonalcoholic individuals for protein III, a neuronal phosphoprotein

Protein phosphorylation is a primary mechanism of intracellular signal transduction, and abnormalities in protein phosphorylation have been implicated in the pathogenesis of several specific diseases. Protein III is a neuronal phosphoprotein that is associated with synaptic vesicles and is probably involved in the regulation of neurotransmitter release. Analysis of 32 postmortem brains has confirmed our previous report that variant forms of protein III with higher apparent molecular weights are found frequently in the brains of alcoholic individuals but rarely in the brains of nonalcoholic individuals who did not suffer from any other medical or neuropsychiatric disorders. Eight of 14 (57%) brain samples from alcoholic individuals and four of eight (50%) brain samples from suspected alcoholic individuals had variant forms, while none of 10 samples from nonalcoholic individuals had variant forms. Previous data indicate that variant forms of protein III are also associated with other neurodegenerative conditions, including various dementias, and, possibly, normal aging.

Hematological complications of alcoholism

Numerous clinical observations support the notion that ethanol has multiple pathologic effects on hematopoietic tissue. The effects of alcohol on blood are diverse. The long-term ingestion of large quantities of ethanol has been shown to alter a substantial number of physiologic and biochemical variables. Abnormalities involving leukocytes, platelets, and erythrocytes may occur singly or in various combinations. Due to the frequent concomitant presence of alcohol-related hepatic disease, nutritional deficiencies, infection, and other chronic diseases, it is often difficult to distinguish the specific hematologic toxicities of alcohol ingestion from the hematologic toxicities of associated morbid conditions. Depressed hematopoietic cell formation (Table 2), increased destruction, and alterations in morphology and function of hematopoietic cells have been described.

Psychiatric implications of altered limbic-hypothalamic-pituitary-adrenocortical activity

Hormones of the limbic-hypothalamic-pituitary-adrenocortical (LHPA) system are much involved in central nervous system regulation. The major LHPA neuropeptides, corticotropin-releasing hormone (CRH), vasopressin (AVP) and corticotropin (ACTH) do not only coordinate the neuroendocrine response to stress, but also induce behavioral adaptation. Transcription and post-translational processing of these neuropeptides is regulated by corticosteroids secreted from the adrenal cortex after stimulation by ACTH and other proopiomelanocortin derived peptides. These steroids play a key role as regulators of cell development, homeostatic maintenance and adaptation to environmental challenges. They execute vitally important actions through genomic effects resulting in altered gene expression and nongenomic effects leading to altered neuronal excitability. Since excessive secretory activity of this particular neuroendocrine system is part of an acute stress response or depressive symptom pattern, there is good reason to suspect that central actions of these steroids and peptides are involved in pathophysiology determining the clinical phenotype, drug response and relapse liability. This overview summarizes the clinical neuroendocrine investigations of the author and his collaborators, while they worked at the Department of Psychiatry in Mainz. The major conclusions from this work were: (1) aberrant hormonal responses to challenges with dexamethasone, ACTH or CRH are reflecting altered brain physiology in affective illness and related disorders; (2) hormones of the LHPA axis influence also nonendocrine behavioral systems such as sleep EEG; (3) physiologically significant interactions exist between LHPA hormones, the thyroid, growth hormone, gonadal and other neuroendocrine systems; (4) hormones of the LHPA axis constitute a bidirectional link between immunoregulation and brain activity; and (5) future psychiatric research topics such as molecular genetics of affective disorders, familial risk studies, drug response analysis and neurobiology of aging will benefit from extended knowledge of neural corticosteroid effects at a clinical, cellular, and molecular level.

Acetylation phenotype in abstinent alcoholics

No association between acetylation phenotype and alcoholism was discovered. Fifty-four percent of both the alcoholic patients and healthy volunteers were rapid acetylators. Acetylation phenotyping is not helpful to the investigation of the genetics of alcoholism.

Human CRH stimulation response during acute withdrawal and after medium-term abstention from alcohol abuse

We compared the baseline cortisol secretory pattern and ACTH and cortisol responses to hCRH (100 micrograms) in eight patients acutely withdrawn from ethanol and 12 patients who abstained from ethanol for two to six weeks. Acute withdrawal from ethanol was characterized by elevated baseline cortisol and blunted ACTH release after hCRH, while medium-term abstention was associated with normalized cortisol secretion but persistence of decreased ACTH output following stimulation. These findings support an altered corticotrophic CRH receptor function in detoxified sober alcoholics. The pathophysiology underlying the blunted ACTH response to hCRH in medium-term ethanol abstention appears to be different from that in acute alcohol withdrawal and hypercortisolemic depression.

Platelet alpha-2-receptor binding and adenylate cyclase activity in panic disorder

The function of the alpha-2-receptor and intracellular effector systems was examined in 39 panic disorder patients and 30 healthy subjects using the platelet as a model system. Alpha-2-receptor density, as reflected by 3H-yohimbine binding, was not different between the two groups. Platelet alpha-2-receptor affinity was decreased (higher Kd) in the panic disorder patients. Other significant abnormalities in the patients included a decreased basal adenylate cyclase activity, reduced EC50 for the epinephrine inhibition of adenylate cyclase activity, and decreased stimulation of adenylate cyclase activity by prostaglandin E1 and sodium fluoride. These results are consistent with a dysfunction in some panic disorder patients at the level of the stimulatory GTP binding regulatory protein, Gs, or the adenylate cyclase catalytic unit. The relationship of these findings to previous studies of noradrenergic function in panic disorder patients is discussed.

Enkephalinase inhibition and precursor amino acid loading improves inpatient treatment of alcohol and polydrug abusers: double-blind placebo-controlled study of the nutritional adjunct SAAVE

We investigated the effects of the amino acid and vitamin mixture SAAVE in inpatient, chemically-dependent subjects to evaluate the role of neurotransmitters in facilitating recovery and adjustment to a detoxified, sober state. SAAVE is formulated from amino acids that are precursors for neurotransmitters and neuromodulators thought to be involved in alcohol and drug seeking behavior. In a double-blind, placebo-controlled, randomized study of 62 alcoholics and polydrug abusers, SAAVE patients had a significantly reduced stress response as measured by the skin conductance level (SCL), and significantly improved Physical Scores and BESS Scores (behavioral, emotional, social and spiritual). After detoxification there was a six-fold decrease in AMA rates when comparing SAAVE vs. placebo groups. In this inpatient treatment experience SAAVE facilitated the rate of recovery and allowed patients to respond more fully and more quickly to the behavioral goals of the program, for example as measured by the BESS Score. The use of SAAVE to achieve enkephalinase inhibition and precursor amino acid loading in the acute inpatient treatment environment provides the practitioner with the potential ability to restore the neurochemical changes inherent to alcoholism and drug abuse. These findings increase our understanding of the clinically relevant neurobiological mechanisms which underlie compulsive disease.

Structural features of human monoamine oxidase A elucidated from cDNA and peptide sequences

Monoamine oxidase (MAO), an important enzyme for the degradation of amine neurotransmitters, has been implicated in neuropsychiatric illness. The amino acid sequence for one form of the enzyme, MAO-A, has been deduced from human cDNA clones and verified against proteolytic peptides. The covalent binding site for the flavin adenine dinucleotide (FAD) cofactor is near the C-terminal region. The presence of features characteristic of the ADP-binding fold suggests that the N-terminal region is also involved in the binding of FAD. These cDNAs should facilitate the study of the structure, function, and intracellular targeting of MAO, as well as the analysis of its expression in normal and pathological states.