The effects of acute and chronic ingestion of ethanol on the autonomic nervous system

Therapeutic potential of Lingjiao Gouteng decoction in acute alcohol intoxication and alcohol-induced brain injury involving the RhoA/ROCK2/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Alcohol misuse persists as a prevalent societal concern and precipitates diverse deleterious consequences, entailing significant associated health hazards including acute alcohol intoxication (AAI). Binge drinking, a commonplace pattern of alcohol consumption, may incite neurodegeneration and neuronal dysfunction. Clinicians tasked with managing AAI confront a dearth of pharmaceutical intervention alternatives. In contrast, natural products have garnered interest due to their compatibility with the human body and fewer side effects. Lingjiao Gouteng decoction (LGD), a classical traditional Chinese medicine decoction, represents a frequently employed prescription in cases of encephalopathy, although its efficacy in addressing acute alcoholism and alcohol-induced brain injury remains inadequately investigated.

AIM OF THE STUDY

To investigate the conceivable therapeutic benefits of LGD in AAI and alcohol-induced brain injury, while delving into the underlying fundamental mechanisms involved.

MATERIALS AND METHODS

We established an AAI mouse model through alcohol gavage, and LGD was administered to the mice twice at the 2 h preceding and 30 min subsequent to alcohol exposure. The study encompassed the utilization of the loss of righting reflex assay, histopathological analysis, enzyme-linked immunosorbent assays, and cerebral tissue biochemical assays to investigate the impact of LGD on AAI and alcohol-induced brain injury. These assessments included a comprehensive evaluation of various biomarkers associated with the inflammatory response and oxidative stress. Finally, RT-qPCR, Western blot, and immunofluorescence staining were carried out to explore the underlying mechanisms through which LGD exerts its therapeutic influence, potentially through the regulation of the RhoA/ROCK2/NF-κB signaling pathway.

RESULTS

Our investigation underscores the therapeutic efficacy of LGD in ameliorating AAI, as evidenced by discernible alterations in the loss of righting reflex assay, pathological analysis, and assessment of inflammatory and oxidative stress biomarkers. Furthermore, the results of RT-qPCR, Western blot, and immunofluorescence staining manifest a noteworthy regulatory effect of LGD on the RhoA/ROCK2/NF-κB signaling pathway.

CONCLUSIONS

The present study confirmed the therapeutic potential of LGD in AAI and alcohol-induced brain injury, and the protective effects of LGD against alcohol-induced brain injury may be intricately linked to the RhoA/ROCK2/NF-κB signaling pathway.

Preparation of Dihydromyricetin-Loaded Self-Emulsifying Drug Delivery System and Its Anti-Alcoholism Effect

Intraperitoneal injection of dihydromyricetin (DMY) has shown promising potential in the treatment of alcoholism. However, its therapeutic effect is limited due to its low solubility, poor stability, and high gut-liver first-pass metabolism, resulting in very low oral bioavailability. In this study, we developed a DMY-loaded self-emulsifying drug delivery system (DMY-SEDDS) to enhance the oral bioavailability and anti-alcoholism effect of DMY. DMY-SEDDS improved the oral absorption of DMY by facilitating lymphatic transport. The area under the concentration-time curve (AUC) of DMY in the DMY-SEDDS group was 4.13-fold higher than in the DMY suspension group. Furthermore, treatment with DMY-SEDDS significantly enhanced the activities of alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) in the liver of mice (p < 0.05). Interestingly, DMY-SEDDS also increased ADH activity in the stomach of mice with alcoholism (p < 0.01), thereby enhancing ethanol metabolism in the gastrointestinal tract and reducing ethanol absorption into the bloodstream. As a result, the blood alcohol concentration of mice with alcoholism was significantly decreased after DMY-SEDDS treatment (p < 0.01). In the acute alcoholism mice model, compared to saline treatment, DMY-SEDDS prolonged the onset of LORR (loss of righting reflex) (p < 0.05) and significantly shortened the duration of LORR (p < 0.01). Additionally, DMY-SEDDS treatment significantly reduced gastric injury in acute alcoholism mice. Collectively, these findings demonstrate the potential of DMY-SEDDS as a treatment in the treatment of alcoholism.

Comparison of the influence of alcohol and cannabis on the dynamics of the accommodative response

PURPOSE

To assess and compare the changes produced by the two most commonly used substances, alcohol and cannabis, on accommodation dynamics.

METHODS

A total of 38 young participants (19 females) were enrolled in the study. They were assigned to two groups: a cannabis group (N = 19) and an alcohol group. Participants in the cannabis group underwent two randomized sessions: a baseline session and a session after smoking a cigarette. Participants in the alcohol group underwent three randomized sessions: a baseline session, a session after the intake of 300 ml of red wine (Alcohol 1), and other after the ingestion of 450 ml of wine (Alcohol 2). For the accommodation assessment, the open-field autorefractor WAM-5500 was used.

RESULTS

The decrease of the mean velocity of the accommodative response produced by Alcohol 2 condition was significantly greater than that observed for Alcohol 1 and Cannabis (p = 0.046). The direction of the accommodation (near-distance and distance-near) had no effect on the deterioration of the accommodation dynamics following substance use. The target distance had a significant effect on the decrease of the mean velocity following substance use (p = 0.002). The decrease of the amplitude of the accommodative response was associated with a decrease of the peak velocity (p = 0.004) and the increase of the accommodative lag (p < 0.001).

CONCLUSIONS

A moderate-high dose of alcohol impairs accommodation dynamics to a greater extent that lower dose of alcohol or smoked cannabis. The deterioration of the accommodation mean speed was higher for a shorter target distance.

Incidence of postoperative hypothermia and its risk factors in adults undergoing orthopedic surgery under brachial plexus block: A retrospective cohort study

Postoperative hypothermia increases patient mortality and morbidity. However, the incidence of, and risk factors for, postoperative hypothermia in patients undergoing surgery under brachial plexus block (BPB) as the primary method of anesthesia remain unclear. This study aimed to determine the incidence of, and risk factors for, postoperative hypothermia in patients undergoing surgery under BPB. We retrospectively analyzed 660 patients aged ≥ 19 years who underwent orthopedic surgery under BPB in our hospital between October 2014 and October 2019. Postoperative hypothermia was defined as a tympanic membrane temperature < 36 °C when the patient arrived in the post-anesthesia care unit. Multivariate logistic regression analysis was performed to identify the independent risk factors for postoperative hypothermia. Postoperative hypothermia was observed in 40.6% (268/660) of patients. Independent risk factors for postoperative hypothermia were lower baseline core temperature before anesthesia (odds ratio [OR] 0.355; 95% confidence interval [CI] 0.185-0.682), alcohol abuse (OR 2.658; 95% CI 1.105-6.398), arthroscopic shoulder surgery (OR 2.007; 95% CI 1.428-2.820), use of fentanyl (OR 1.486; 95% CI 1.059-2.087), combined use of midazolam and dexmedetomidine (OR 1.816; 95% CI 1.268-2.599), a larger volume of intravenous fluid (OR 1.001; 95% CI 1.000-1.002), and longer duration of surgery (OR 1.010; 95% CI 1.004-1.017). Postoperative hypothermia is common in adult patients undergoing orthopedic surgery under BPB. The risk factors identified in this study should be considered to avoid postoperative hypothermia in these patients.

Alcohol-Induced Neuropathy in Chronic Alcoholism: Causes, Pathophysiology, Diagnosis, and Treatment Options

Purpose of the Review

Alcohol abuse causes a wide range of disorders that affect the nervous system. These include confusion, cerebellar ataxia, peripheral neuropathy, and cognitive impairment. Chronic and excessive alcohol consumption is the primary cause of peripheral neuropathy. It is worth noting that peripheral neuropathy has no reliable treatment due to the poor understanding of its pathology.

Recent Findings

Coasting is a major feature of alcoholic neuropathy, largely due to chronic alcohol abuse. Its major features are hyperalgesia, allodynia, and burning pain. Even though much research was done in this area, still we do not have a full understanding of the mechanism of alcoholic neuropathy. However, some theories have been proposed. These include direct or indirect effects of alcohol metabolites, impaired axonal transport, suppressed excitatory nerve pathway activity, or imbalance in neurotransmitters. Activation of spinal cord microglia, mGlu5 spinal cord receptors, and hypothalamic-pituitary-adrenal axis also seem to be implicated in the pathophysiology of this alcoholic neuropathy. The goal of treatment is to impede further damage to the peripheral nerves while also restoring their normal physiology. Alcohol abstinence, intake of balanced diets, and treatment with medications are suggested including benfotiamine, alpha-lipoic acid, acetyl-l-carnitine, vitamin E, methylcobalamin, myo-inositol, N-acetylcysteine, capsaicin, tricyclic antidepressants, or antiepileptic drugs.

Summary

This review focuses on the many pathways that play a role in the onset and development of alcohol-induced neuropathy, as well as present the possible treatment strategies of this disorder, providing insights into a further search of new treatment modalities.

Increased QT Dispersion Is Linked to Worse Outcomes in Patients Hospitalized for Out-of-Hospital Cardiac Arrest

Background The incidence and mortality of out-of-hospital cardiac arrest (OHCA) remains high, but predicting outcomes is challenging. Being able to better assess prognosis of hospitalized patients after return of spontaneous circulation would enable improved management of survival expectations. In this study, we assessed the predictive value of ECG indexes in hospitalized patients with OHCA. Methods and Results PR interval and QT interval corrected by the Bazett formula (QTc) for all leads were calculated from standard 12-lead ECGs 24 hours after return of spontaneous circulation in 93 patients who were hospitalized following OHCA. PR interval and QT and QTc duration did not differentiate OHCA survivors and nonsurvivors. However, QT and QTc dispersion was significantly increased in patients who died during hospitalization compared with survivors discharged from the hospital (P<0.01). Logistic regression indicated a strong association between increased QT dispersion and in-hospital mortality (P<0.0001; area under the curve, 0.8918 for QT dispersion and 0.8673 for QTc dispersion). Multinomial logistic regression indicated that the increase of QTc dispersion correlated with worse Cerebral Performance Category scores at discharge (P<0.001; likelihood ratio, 51.42). There was also significant correlation between dispersion measures and serum potassium at the time of measurement and between dispersion measures and cumulative epinephrine administration. No difference existed regarding the number of measurable leads. Conclusions Lesser QT and QTc dispersion at 24 hours after return of spontaneous circulation was significantly associated with survival and neurologic status at discharge. Routine evaluation of QT and QTc dispersion during hospitalization following return of spontaneous circulation might improve outcome prognostication for patients hospitalized for OHCA.

Heart rate variability as a potential biomarker for alcohol use disorders: A systematic review and meta-analysis

BACKGROUND

Alcohol use disorders (AUDs) have been found to be associated with elevated cardiovascular risk. The autonomic nervous system is considered to play a role in this association. Heart rate variability (HRV) has been employed to measure parasympathetic activity in AUDs patients in some studies; however, the results are not consistent, and the adopted HRV indices vary across studies. A meta-analysis should be helpful for clarifying this topic.

METHODS

We gathered studies about measuring HRV in AUDs patients and healthy participants from databases. HRV was analyzed in several ways: parasympathetic function in hierarchical order (main analysis), total variability, and specific parasympathetic indices. Specific parasympathetic indices were further separated into high-frequency power (HF) and root mean square of the successive differences (RMSSD). For comparing the above values in patients with AUDs and in healthy individuals, we adopted the random effects model to calculate the standardized mean difference.

RESULTS

Of the 144 screened studies, 15 were included in the quantitative analysis. In the comparison of parasympathetic function in hierarchical order, HRV in AUDs patients was significantly lower than in healthy individuals (Hedges'g = -0.4301, 95% CI [-0.7601 to -0.1000], p=0.0106, I² = 83.8%). Regarding total variability and RMSSD, AUDs patients also had significantly lower values than healthy controls. However, the differences of specific parasympathetic indices and HF were not significantly different.

CONCLUSION

Our results support the view that AUDs patients have reduced parasympathetic activity. Total variability and RMSSD are suitable indices for presenting reduced HRV in patients with AUDs.

Ethanol Elevates Excitability of Superior Cervical Ganglion Neurons by Inhibiting Kv7 Channels in a Cell Type-Specific and PI(4,5)P2-Dependent Manner

Alcohol causes diverse acute and chronic symptoms that often lead to critical health problems. Exposure to ethanol alters the activities of sympathetic neurons that control the muscles, eyes, and blood vessels in the brain. Although recent studies have revealed the cellular targets of ethanol, such as ion channels, the molecular mechanism by which alcohol modulates the excitability of sympathetic neurons has not been determined. Here, we demonstrated that ethanol increased the discharge of membrane potentials in sympathetic neurons by inhibiting the M-type or Kv7 channel consisting of the Kv7.2/7.3 subunits, which were involved in determining the membrane potential and excitability of neurons. Three types of sympathetic neurons, classified by their threshold of activation and firing patterns, displayed distinct sensitivities to ethanol, which were negatively correlated with the size of the Kv7 current that differs depending on the type of neuron. Using a heterologous expression system, we further revealed that the inhibitory effects of ethanol on Kv7.2/7.3 currents were facilitated or diminished by adjusting the amount of plasma membrane phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). These results suggested that ethanol and PI(4,5)P2 modulated gating of the Kv7 channel in superior cervical ganglion neurons in an antagonistic manner, leading to regulation of the membrane potential and neuronal excitability, as well as the physiological functions mediated by sympathetic neurons.

Gender Differences in Anxiety and Depression before and after Alcohol Detoxification: Anxiety and Depression as Gender-Related Predictors of Relapse

BACKGROUND/AIMS

The aim of this prospective study was to estimate gender differences in anxiety, depression, and alcohol use severity among patients with alcohol use disorder (AUD) before and after detoxification program and within 12 months after discharge.

METHODS

AUD severity, state and trait anxiety, and depression were assessed in 187 patients entering an inpatient alcohol detoxification program. Follow-up assessments were performed at 6 and 12 months after discharge. A between- and within-subjects analyses explored gender differences. The predictive value of anxiety and depression for alcohol relapse was analyzed by logistic and linear regression in both genders.

RESULTS

Females had higher levels of anxiety and depression than males both at admission and after discharge. Trait anxiety and depression significantly increased 6 months after discharge in males and females respectively. Both state and trait anxiety levels at the 6-month follow-up predicted alcohol relapse at the 12-month follow-up in males. Conversely, in females, depression level at the 6-month follow-up was a predictor of relapse at the 12-month follow-up.

CONCLUSIONS

In both genders, the psychopathological dimension that showed the most significant worsening at 6-month follow-up (i.e., anxiety in males and depression in females) was found to be a significant predictor of relapse at the 12-month follow-up.

Multiple territory watershed infarcts following spinal anaesthesia

Hypotension is one of the most common complications of spinal anaesthesia (SA). The intraoperative drop in the blood pressure is clearly associated with increased morbidity and mortality. In order to increase the awareness of this complication, we report a case of devastating stroke following an SA in a previously well woman with risk factors for vascular diseases. The patient developed multiple territory watershed infarcts and she eventually died from aspiration pneumonia 14 days after hospitalisation. The case highlights the risk of hypotension complicating SA.

Substance abuse in emergency department patients with unexplained syncope

Current data suggest that up to 60 % of patients presenting to the ED with syncope leave the hospital without a defined etiology. Although a relationship between syncope and substance abuse has been described, no study to date has looked at the relationship between syncope of unknown etiology and substance abuse in patients presenting to the ED. The objective of the study was to determine whether a history of or current substance abuse is associated with an increased incidence of syncope of unknown etiology in ED patients. A prospective, observational, cohort study of consecutive ED patients aged ≥18 who presented with syncope was conducted between 6/03 and 7/06. Patients were queried in the ED and charts reviewed about a history of or current substance abuse. Substance abuse was defined as consumption of >2 alcoholic beverages nightly, repetitive use of any illicit substances, or documentation by the patient's physician of concern regarding suspected substance abuse. Data were analyzed using SAS with Chi-squared and Fisher's exact tests. We enrolled 518 patients who presented to the ED after syncope, 161 of whom did not have an identifiable etiology for their syncopal event. 62 patients had a history of, or current substance abuse. Among patients with a history of, or current substance abuse, 45 % had unexplained syncope, as opposed to 29 % of patients without such a history (p = 0.01). Our results suggest that prior and current substance abuse is associated with increased incidence of syncope of unknown etiology. Patients evaluated in the ED or even hospitalized with syncope of unknown etiology may benefit from substance abuse screening and possibly detoxification referral.

Purinergic signalling in the urinary tract in health and disease

Purinergic signalling is involved in a number of physiological and pathophysiological activities in the lower urinary tract. In the bladder of laboratory animals there is parasympathetic excitatory cotransmission with the purinergic and cholinergic components being approximately equal, acting via P2X1 and muscarinic receptors, respectively. Purinergic mechanosensory transduction occurs where ATP, released from urothelial cells during distension of bladder and ureter, acts on P2X3 and P2X2/3 receptors on suburothelial sensory nerves to initiate the voiding reflex, via low threshold fibres, and nociception, via high threshold fibres. In human bladder the purinergic component of parasympathetic cotransmission is less than 3 %, but in pathological conditions, such as interstitial cystitis, obstructed and neuropathic bladder, the purinergic component is increased to 40 %. Other pathological conditions of the bladder have been shown to involve purinoceptor-mediated activities, including multiple sclerosis, ischaemia, diabetes, cancer and bacterial infections. In the ureter, P2X7 receptors have been implicated in inflammation and fibrosis. Purinergic therapeutic strategies are being explored that hopefully will be developed and bring benefit and relief to many patients with urinary tract disorders.

Poor autonomic nervous system functioning during sleep in recently detoxified alcohol-dependent men and women

BACKGROUND

Alcoholism is considered an important risk factor for cardiovascular (CV) disease. Autonomic nervous system (ANS) function is a major indicator of CV health. Sleep is a suitable model to investigate ANS activity free from wake-related confounders. We investigated nighttime ANS functioning, and the relation between ANS activity and severity of alcohol dependence in chronic alcoholism.

METHODS

Fourteen recently abstaining alcoholics (age: 42.0 ± 9.0 years, 7 women) and 16 age- and sex-matched controls (age: 45.2 ± 9.1 years, 8 women) underwent a night of standard clinical polysomnography, including electrocardiographic recording. Time- and frequency-domain spectral analysis of heart rate variability (HRV) was performed across hours of the night and during artifact-free epochs of stable sleep and wakefulness (presleep wakefulness, rapid-eye-movement [REM], and non-REM sleep).

RESULTS

Alcoholics had a poorer subjective and objective sleep quality compared to controls. Across the night, alcoholic men and women had elevated heart rate, reduced total HRV, that is, lower standard deviation of normal-to-normal interbeat intervals, and reduced high frequency (HF) activity (assessed by the HF power and by the square root of the mean squared of successive heart period differences). This ANS pattern was most apparent at the beginning of the night. None of the ANS measures was associated with lifetime alcohol consumption or duration of alcohol dependence.

CONCLUSIONS

Our results show that ANS functioning is disrupted during the night, even in undisturbed sleep periods, indicating poor CV functioning in recently detoxified alcohol-dependent men and women.

Influence of acute alcohol ingestion on sympathetic neural responses to orthostatic stress in humans

Acute alcohol consumption is reported to decrease mean arterial pressure (MAP) during orthostatic challenge, a response that may contribute to alcohol-mediated syncope. Muscle sympathetic nerve activity (MSNA) increases during orthostatic stress to help maintain MAP, yet the effects of alcohol on MSNA responses during orthostatic stress have not been determined. We hypothesized that alcohol ingestion would blunt arterial blood pressure and MSNA responses to lower body negative pressure (LBNP). MAP, MSNA, and heart rate (HR) were recorded during progressive LBNP (-5, -10, -15, -20, -30, and -40 mmHg; 3 min/stage) in 30 subjects (age 24 ± 1 yr). After an initial progressive LBNP (pretreatment), subjects consumed either alcohol (0.8 g ethanol/kg body mass; n = 15) or placebo (n = 15), and progressive LBNP was repeated (posttreatment). Alcohol increased resting HR (59 ± 2 to 65 ± 2 beats/min, P < 0.05), MSNA (13 ± 3 to 19 ± 4 bursts/min, P < 0.05), and MSNA burst latency (1,313 ± 16 to 1,350 ± 17 ms, P < 0.05) compared with placebo (group × treatment interactions, P < 0.05). During progressive LBNP, a pronounced decrease in MAP was observed after alcohol but not placebo (group × time × treatment, P < 0.05). In contrast, MSNA and HR increased during all LBNP protocols, but there were no differences between trials or groups. However, alcohol altered MSNA burst latency response to progressive LBNP. In conclusion, the lack of MSNA adjustment to a larger drop in arterial blood pressure during progressive LBNP, coupled with altered sympathetic burst latency responses, suggests that alcohol blunts MSNA responses to orthostatic stress.

Hemodynamics in the immediate post-transplantation period in alcoholic and viral cirrhosis

AIM: To study the hemodynamics in the immediate post transplant period and compare patients with alcoholic vs viral cirrhosis.

METHODS: Between 2000-2003, 38 patients were transplanted for alcoholic cirrhosis and 28 for postviral cirrhosis. Heart rate (HR), central venous pressure (CVP), mean arterial pressure (MAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), systemic vascular resistance index (SVRI), pulmonary artery pressure (PAP), and pulmonary vascular resistance index (PVRI) were measured immediately and 24 h post transplantation.

RESULTS: Hyperdynamic circulation persisted at 24 h following transplantation with an elevated CI of 5.4 ± 1.3 L/(min × m²) and 4.9 ± 1.0 L/(min × m²) in the viral and alcoholic groups, respectively, and was associated with a decreased SVRI. Within the first 24 h, there was a significant decrease in HR and increase in MAP; the extent of the change was similar in both groups. The CVP, PCWP, and SVRI increased, and CI decreased in the viral patients, but not the alcoholic patients. Alcoholics showed a lower PVRI (119 ± 52 dynes/(cm⁵× m²) vs 166 ± 110 dynes/(cm⁵× m²), P < 0.05) and PAP (20 ± 7 mmHg vs 24 ± 7 mmHg, P < 0.05) compared to the viral group at 24 h.

CONCLUSION: Hyperdynamic circulation persists in the immediate post-transplant period with a faster improvement in the viral group. Alcoholic patients have a more pronounced pulmonary vasodilatation.

p38SJ, a novel DINGG protein protects neuronal cells from alcohol induced injury and death

Ethanol induces neuronal cell injury and death by dysregulating several signaling events that are controlled, in part, by activation of MAPK/ERK1/2 and/or inactivation of its corresponding phosphatase, PP1. Recently, we have purified a novel protein of 38 kDa in size, p38SJ, from a callus culture of Hypericum perforatum, which belongs to an emerging DINGG family of proteins with phosphate binding activity. Here, we show that treatment of neuronal cells with p38SJ protects cells against injury induced by exposure to ethanol. Furthermore, pre-treatment of neuronal cells with p38SJ diminishes the level of the pro-apoptotic protein Bax and some events associated with apoptosis such as caspase 3 cleavage. In addition, by inducing stress, alcohol can elevate production of reactive oxygen species (ROS) that leads to a decrease in the activity of superoxide dismutase (SOD). Our results showed that p38SJ restores the activity of SOD in the ethanol treated neuronal cells. These observations provide a novel biological tool for developing new approaches for preventing neuronal cell death induced by ethanol and possibly treatment of neurological disorders associated with alcohol abuse.

Brewing controversies: Darwinian perspective on the adaptive and maladaptive effects of caffeine and ethanol as dietary autonomic modulators

Ethanol and caffeine are two of the oldest human drugs. Their pervasive integration into the modern human diet may reflect behavioral attempts to correct maladaptations induced by evolutionary displacement of the autonomic system. The dietary adoption of caffeine may parallel the emergence of cognition as an independent basis of competition. Enhancement of the cognitive ability to gather and process information likely evolved as a valuable adjunct to physical behavior in prehistoric fight-or-flight encounters. Caffeine effectively exploits this pre-existing association between adrenergic activity and cognitive readiness, leading to its use in the modern environment where success in competition increasingly depends on cognitive, rather than physical, prowess. Ethanol may have emerged as a dietary means to buffer the maladaptive chronic sympathetic activation and fear response associated with stressful lifestyles and the social phobias associated with the dissolution of kin networks. We explore the health implications of ethanol and caffeine use, with particular attention to their acute and chronic effects on the autonomic axis. The putative protective effects of ethanol in surviving major trauma or reducing inflammation and heart disease may relate to tempering the behavioral and cardiovascular consequences of catastrophic or chronic sympathetic activation. Acute or chronic abuse of ethanol manifests paradoxical pro-adrenergic effects such as tremors and insomnia that may partly represent compensatory responses. Compensatory remodeling may also explain why confirmation of detrimental effects related to caffeine-induced sympathetic activation has proven elusive; indeed, paradoxical pro-vagal benefits may eventually be recognized. Ethanol and caffeine are potential agents that may beneficially expand the dynamic range of the autonomic system. In an environment where the Darwinian value of knowledge has increasingly supplanted that of physical traits, the consumption of caffeine and alcohol may represent both a cause and an effect of modern human evolution.

Biphasic changes in cardiac excitation-contraction coupling early in chronic alcohol exposure

Although the negative inotropic effects of both acute and chronic ethanol (EtOH) exposure are well known, little is known concerning the acute-to-chronic transition of such effects. In this study, our objective was to address this question by detailing the effects that acute EtOH exposure induces on cellular excitation-contraction (EC) coupling and, subsequently, comparing whether and how such changes translate to the early chronic EtOH condition in a rat model known to develop alcohol-induced cardiomyopathy. Acute EtOH exposure, as formerly reported, indeed induced dose-dependent negative inotropic changes in cellular EC coupling, manifest as reductions in cell shortening, Ca2+ transient amplitude, Ca2+ decay rate, and sarcoplasmic reticulum Ca2+ content of isolated rat ventricular cardiac myocytes. Supplementary to this, we found Ca2+ spark character not to be significantly affected by acute EtOH exposure. In contrast, the results obtained from cardiac myocytes isolated from rats fed a diet containing ∼9% (vol/vol) EtOH for 1 mo revealed changes in these parameters reflecting positive inotropy, whereas at 3 mo, these parameters again reflected negative inotropy similar but not identical to that induced by acute EtOH exposure. No significant changes were evident at either 1- or 3-mo chronic EtOH administration in echocardiographic parameters known to be perturbed in alcoholic cardiomyopathy (ACM), thus indicating that we were examining an asymptomatic stage in chronic EtOH administration consistent with an acute-to-chronic transition phase. Continued study of such transition-phase events should provide important insight into which molecular-cellular components of EC coupling play pivotal roles in EtOH-induced disease processes, such as ACM.

Direct effect of ethanol on human vascular function

Epidemiological studies indicate that moderate ethanol consumption reduces cardiovascular mortality. Cellular and animal data suggest that ethanol confers beneficial effects on the vascular endothelium and increases the bioavailability of nitric oxide. The purpose of this study was to assess the effect of ethanol on endothelium-dependent, nitric oxide-mediated vasodilation in healthy human subjects. Forearm blood flow (FBF) was determined by venous occlusion plethysmography in healthy human subjects during intra-arterial infusions of either methacholine (0.3, 1.0, 3.0, and 10.0 mcg/min, n = 9), nitroprusside (0.3, 1.0, 3.0, and 10.0 mcg/min, n = 9), or verapamil (10, 30, 100, and 300 mcg/min, n = 8) before and during the concomitant intra-arterial infusions of ethanol (10% ethanol in 5% dextrose). Additionally, a time control experiment was conducted, during which the methacholine dose-response curve was measured twice during vehicle infusions ( n = 5). During ethanol infusion, mean forearm and systemic alcohol levels were 227 ± 30 and 6 ± 0 mg/dl, respectively. Ethanol infusion alone reduced FBF (2.5 ± 0.1 to 1.9 ± 0.1 ml·dl−1·min−1, P < 0.05). Despite initial vasoconstriction, ethanol augmented the FBF dose-response curves to methacholine, nitroprusside, and verapamil ( P < 0.01 by ANOVA for each). To determine whether this augmented FBF response was related to shear-stress-induced release of nitric oxide, FBF was measured during the coinfusion of ethanol and NG-nitro-l-arginine (l-NAME; n = 8) at rest and during verapamil-induced vasodilation. The addition of l-NAME did not block the ability of ethanol to augment verapamil-induced vasodilation. Ethanol has complex direct vascular effects, which include basal vasoconstriction as well as potentiation of both endothelium-dependent and -independent vasodilation. None of these effects appear to be mediated by an increase in nitric oxide bioavailability, thus disputing findings from preclinical models.

The incidence and risk factors for hypotension after spinal anesthesia induction: an analysis with automated data collection

We sought to identify factors that are associated with hypotension after the induction of spinal anesthesia (SpA) by using an anesthesia information management system. Hypotension was defined as a decrease of mean arterial blood pressure of more than 30% within a 10-min interval, and relevance was defined as a therapeutic intervention with fluids or pressors within 20 min. From January 1, 1997, to August 5, 2000, data sets from 3315 patients receiving SpA were recorded on-line by using the automatic anesthesia record keeping system NarkoData. Hypotension meeting the predefined criteria occurred in 166 (5.4%) patients. Twenty-nine patient-, surgery-, and anesthesia-related variables were studied by using univariate analysis for a possible association with the occurrence of hypotension after SpA. Logistic regression with a forward stepwise algorithm was performed to identify independent variables (P < 0.05). The discriminative power of the logistic regression model was checked with a receiver operating characteristic curve. Calibration was tested with the Hosmer-Lemeshow goodness-of-fit test. The univariate analysis identified the following variables to be associated with hypotension after SpA: age, weight, height, body mass index, amount of plain bupivacaine 0.5% used for SpA, amount of colloid infusion before puncture, chronic alcohol consumption, ASA physical status, history of hypertension, urgency of surgery, surgical department, sensory block height of anesthesia, and frequency of puncture. In the multivariate analysis, independent factors for relevant hypotension after SpA consisted of three patient-related variables ("chronic alcohol consumption," odds ratio [OR] = 3.05; "history of hypertension," OR = 2.21; and the metric variable "body mass index," OR = 1.08) and two anesthesia-related variables ("sensory block height," OR = 2.32; and "urgency of surgery," OR = 2.84). The area of 0.68 (95% confidence interval, 0.63-0.72) below the receiver operating characteristic curve was significantly greater than 0.5 (P < 0.01). The goodness-of-fit test showed a good calibration of the model (H = 4.3, df = 7, P = 0.7; C = 7.3, df = 8, P = 0.51). This study contributes to the identification of patients with a high risk for hypotension after SpA induction, with the risk increasing two- or threefold with each additional risk factor.

IMPLICATIONS

By using automated data collection, 5 (chronic alcohol consumption, history of hypertension, body mass index, sensory block height, and urgency of surgery) of 29 variables could be detected as having an association with hypotension after spinal anesthesia induction. The knowledge of these risk factors should be useful in increasing vigilance in those patients most at risk for hypotension, in allowing a more timely therapeutic intervention, or even in suggesting the use of alternative methods of spinal anesthesia, such as titrated continuous or small-dose spinal anesthesia.

Chronic ethanol consumption impairs adrenoceptor- and purinoceptor-mediated relaxations of isolated rat detrusor smooth muscle

OBJECTIVE

To investigate the effects of chronic ethanol consumption on the reactivity of detrusor smooth muscle.

MATERIALS AND METHODS

Eight male rats received ethanol (7.2% v/v) in a modified liquid diet for 4 weeks. Two control groups were assessed; eight rats in one group were fed sucrose and received a liquid diet, and 12 rats in the second group received standard rat chow and water for 4 weeks. The reactivity of detrusor smooth muscle strips from ethanol-fed animals and control animals was evaluated in organ chambers.

RESULTS

The relaxation response elicited by isoprenaline or adenosine was unaffected in the both control groups while it was significantly inhibited, with decreased maximum responses and pD2 values, in the ethanol-fed group. Contractile responses of detrusor smooth muscle to carbachol or 80 mmol/L KCl and relaxant responses to papaverine were similar in the control groups and the ethanol-fed group. There was no change in agonist potency among the groups.

CONCLUSION

Chronic ethanol consumption impairs beta-adrenoceptor- and purinoceptor-mediated relaxation but not cholinoceptor-mediated contraction of the rat detrusor smooth muscle. Thus, it appears that different regulatory mechanisms are involved in ethanol-induced alterations in beta-adrenergic, purinergic and muscarinic receptors in detrusor strip.

Risk factors for syncope in a community-based sample (the Framingham Heart Study)

The epidemiology of syncope has not been well described. Prior studies have examined risk factors for syncope in hospital-based or other acute or long-term care settings. To determine risk factors for syncope in a community-based sample, we performed a nested case-control study. We examined reports of syncope in Framingham Heart Study participants who underwent routine clinic visits from 1971 to 1990. For each syncope case (n = 543) 2 controls were matched for age, sex, and examination period. Mean age of subjects was 67 years (range 25 to 95); 59% were women. History of stroke or transient ischemic attack, history of myocardial infarction, high blood pressure, use of antihypertensive medication, use of other cardiac medication, smoking, alcohol intake, body mass index, systolic blood pressure, diastolic blood pressure, heart rate, atrial fibrillation, PR interval prolongation, interventricular block, and diabetes or elevated glucose level were examined as potential predictors. Using conditional logistic regression analysis, the predictors of syncope included a history of stroke or transient ischemic attack (odds ratio [OR] 2.56, 95% confidence interval [CI] 1.62 to 4.04), use of cardiac medication (OR 1.67, 95% CI 1.21 to 2. 30), and high blood pressure (OR 1.46, 95% CI 1.14 to 1.88). Lower body mass index was marginally associated with syncope (OR per 4 kg/m(2) decrement 1.10, 95% CI 0.99 to 1.22), as were increased alcohol intake (OR per 5 oz/week 1.11, 95% CI 0.99 to 1.26), and diabetes or an elevated glucose level (OR 1.29, 95% CI 0.96 to 1.75). To our knowledge, this study represents the first community-based study of risk factors for syncope.

Alcohol potentiates orthostatic hypotension : implications for alcohol-related syncope

BACKGROUND

Alcohol consumption may be linked to syncopal events. The mechanisms by which alcohol may induce syncope are unknown. Impairment of the response to orthostatic stress may be involved. Using a double-blind, randomized, placebo-controlled study, we tested the hypothesis that short-term alcohol intake causes orthostatic hypotension because of an impairment in the vasoconstrictor response to orthostatic stress.

METHODS AND RESULTS

We examined the effects of alcohol on blood pressure, heart rate, and forearm vascular resistance (FVR) during orthostatic stress achieved by stepwise increases in lower-body negative pressure (LBNP) in 14 healthy young volunteers. During the placebo session, blood pressure did not change significantly during LBNP at -5, -10, and -20 mm Hg. A significant decrease in blood pressure was evident only at -40 mm Hg. In contrast, blood pressure fell significantly at all levels of LBNP during the alcohol session. Compared with placebo, alcohol potentiated the hypotensive responses to LBNP, particularly at -40 mm Hg, when the decrease in systolic blood pressure after alcohol intake (-14 mm Hg) was double that after placebo intake (-7 mm Hg). FVR increased with LBNP after placebo. However, after alcohol intake, FVR did not increase during LBNP despite the potentiated decrease in blood pressure. FVR responses during LBNP were reduced during alcohol compared with placebo consumption (P=0.04).

CONCLUSIONS

Short-term alcohol consumption elicits hypotension during orthostatic stress because of impairment of vasoconstriction. These findings have implications for the understanding of the hemodynamic effects of alcohol and, in particular, for understanding syncopal events that occur in association with alcohol intake.

Death as a result of heat stroke in a vehicle: an adult case in winter confirmed with reconstruction and animal experiments

A 54-year-old man was found dead in the driver's seat of his vehicle on a winter's day. Investigations of the vehicle revealed that the engine was running, and the car heater was left on with the maximum temperature and velocity. The body was found excessively sweating. Rectal temperature of the body was 43 degrees C at 10 h post mortem. In autopsy, several superficial skin burns were observed on the face, the shoulders and the legs. The lungs were heavily congested and hemorrhagic. The liver showed typical alcohol-induced micronodular cirrhosis. The alcohol concentrations were 0.17% in the blood of both the left and the right heart, 0.17% in the femoral-vein blood, 0.21% in the bladder urine and 0.34% in the gastric contents. A reconstruction experiment demonstrated that the temperature inside the vehicle rose rapidly and reached 50-58 degrees C in 3 h. Animal experiments showed that the temperature threshold for rats to succumb to heat was between 40 and 45 degrees C. This case shows that heat stroke in a vehicle can occur in adults with chronic diseases or alcoholism, such as in this particular case, even in the winter.

Concurrent use of cocaine and alcohol is more potent and potentially more toxic than use of either alone--a multiple-dose study

BACKGROUND

Simultaneous abuse of cocaine and alcohol is widespread and increasingly detected in patients seeking emergent care. This double-blind, randomized, within-subjects study used a paradigm more closely approximating practices of drug abusers to better understand the pathogenesis of cocaine-alcohol abuse.

METHODS

Subjects meeting DSM-IV criteria for cocaine dependence and alcohol abuse participated in three drug administration sessions: four doses of intranasal cocaine (1 mg/kg every 30 min) with oral alcohol (1 g/kg) administered following the initial cocaine dose and a second dose (120 mg/kg) at 60 min calculated to maintain plasma alcohol concentration at approximately 100 mg/dL during cocaine administration; four doses of cocaine/placebo alcohol; four doses of cocaine placebo/alcohol. Pharmacokinetic, physiological, and behavioral effects were followed over 8 hours.

RESULTS

Cocaine-alcohol produced greater euphoria and increased perception of well-being relative to cocaine. Heart rate significantly increased following cocaine-alcohol administration relative to either drug alone. Cocaine concentrations were greater following cocaine-alcohol administration. Cocaethylene had a longer halflife with increasing concentrations relative to cocaine at later time points.

CONCLUSIONS

Enhanced psychological effects during cocaine-alcohol abuse may encourage ingestion of larger amounts of these substances over time placing users at heightened risk for greater toxicity than with either drug alone.

Effect of ethanol drinking, hangover, and exercise on adrenergic activity and heart rate variability in patients with a history of alcohol-induced atrial fibrillation

To elucidate the mechanism of alcohol-induced atrial fibrillation (AF) we studied the heart rate variability and parameters of the adrenergic system during alcohol intake, hangover, and exercise in 6 men (mean age 43 years) prone to alcohol-induced AF, together with 6 age-matched controls. The ambulatory (15 hour) electrocardiogram was recorded and blood samples were taken for lymphocytic beta adrenoceptor, plasma catecholamine, and cyclic adenosine monophosphate (cAMP) measurements before and after alcohol intake (blood alcohol 1.5 per thousand), during hangover, and after a standardized bicycle exercise test. The beta-adrenoceptor density in lymphocytes was unchanged in the control group after alcohol intake or during hangover. Each of the AF patients had an increase in beta-adrenoceptor density after ethanol drinking (mean increase 29%, p <0.05). The hangover or exercise beta-receptor values did not differ from those in corresponding controls. Plasma adrenaline concentration tended to decrease and noradrenaline to increase after drinking and during hangover in both groups. Plasma cAMP levels were lower in patients after drinking than in controls (p <0.05). The exercise values of the adrenergic parameters were very similar in AF patients whether or not preceded by alcohol. Analysis of ambulatory electrocardiography showed a very low rate of ectopic beats in both AF patients and controls. Analysis of heart rate variability revealed a tendency toward an increase in sympathetic/parasympathetic component ratio (low-frequency/high-frequency ratio) in AF patients, but not in controls, after ethanol drinking. In conclusion, no signs of arrhythmogenic cardiac disease were detected in patients with AF to explain the tendency toward AF. Increases in beta-adrenoceptor density and low-frequency/high-frequency ratio during ethanol intoxication in patients with AF suggest an exaggerated sympathetic reaction.

Psychiatric illness and syncope

Studies have reported a high prevalence of psychiatric illness in patients with syncope, particularly among those with syncope of unknown etiology. Although mortality rates for patients with syncope and psychiatric disorders tend to be lower than for patients with cardiac cause for syncope, treatment of these psychiatric illnesses appears to result in lower rates of recurrence of the symptoms. The authors recommend an assessment for psychiatric illness in those patients in whom the initial evaluation does not suggest an organic cause for syncope. Further studies are needed to elucidate the pathophysiologic mechanisms for syncope and the effects of treatment of psychiatric illness on recurrence of syncope.

Hemodynamic alterations in alcohol-related transitory hypertension

Alcoholic patients are often transiently hypertensive (tHT) during days 1-3 of withdrawal but become normotensive thereafter. However, at 3-4 weeks postwithdrawal these tHT patients may still show exaggerated blood pressure rises to isometric handgrip exercise. We examined the hemodynamic mechanisms associated with persistent altered pressure response. Forty-two alcoholic inpatients were equally divided into three subgroups based on admission BPs: transitory hypertensive (tHT;BP > or = 160/95 mmHg), transitory borderline hypertensive (tBH; 140/ 90 < or = BP < 160/95), and normotensive (NT; BP < 140/90). After 3-4 weeks of sobriety, the alcoholics and a normotensive nonalcoholic group (CONTs; n = 14) were tested during rest and an isometric handgrip task. Impedance cardiographic evaluation at both times showed elevated peripheral resistance, elevated heart rate, and reduced stroke volume in tHTs. Liquor consumption was found to be highly predictive of the altered hemodynamic and BP activity. Alcoholic patients with acute withdrawal hypertension (1-3 days) may show a persistent alteration of BP regulation even when resting pressures are normal.

Psychiatric illnesses in patients with syncope

PURPOSE

To determine the prevalence of psychiatric disorders among patients with syncope; the relationship between psychiatric disorders and the cause of syncope; and the outcome of syncope patients with psychiatric disorders.

PATIENTS AND METHODS

In a prospective cohort study in a university-affiliated medical center, hospitalized and ambulatory patients with syncope underwent a standardized medical and psychiatric evaluation consisting of the Diagnostic Interview Schedule (DIS) sections for somatization, panic, generalized anxiety, major depression disorders, and drug and alcohol dependence and abuse disorders.

RESULTS

Of 414 patients who completed the DIS, 82 (20%) met the criteria for at least one of the psychiatric disorders or alcohol/drug disorders. Patients with at least one of the four major psychiatric disorders (n = 58) were more likely to report > or = 4 syncopal events in the past year (odds ratio (OR) 2.5, P < 0.04); and to have prodromal symptoms prior to syncopal events (OR 2.4, P < 0.04) than were patients without psychiatric disorders. Syncope patients with only alcohol/drug disorders (n = 24) were more likely to be male (OR 7.7, P < 0.001) and younger than 65 years old (OR 4.5, P < 0.001) than patients without alcohol/drug disorders. One-year recurrence rate for syncope in patients with any psychiatric diagnosis was 35%, compared to 15% in those without a psychiatric disorder (P < 0.0001). Physicians were able to recognize potential psychiatric or alcohol/drug disorders in 70% of patients with more than one psychiatric disorder, but failed to note or treat 60% of the patients with only one of the assessed disorders.

CONCLUSIONS

We recommend screening for psychiatric disorders in patients with unexplained syncope, especially in individuals with recurrent syncope and multiple physical symptoms, or for males who are under 65 years of age.

Alcohol consumption and physical fitness among young adults

The relationship between alcohol consumption and physical fitness was analyzed using data from the baseline examination of the Coronary Artery Disease Risk Development In Young Adults study (CARDIA), a longitudinal study of the evolution of risk factors for cardiovascular disease in Black and White men and women aged 18-30 years. Two parameters of submaximal exercise treadmill testing were evaluated: time to heart rate 130 and duration of the treadmill test. In men and women qualified for treadmill testing, time to reach heart rate 130 was positively associated with ethanol intake. The relationship between fitness and ethanol intake persisted in sex-specific analysis after adjustment for age, ethnicity, systolic blood pressure, sum of subscapular and triceps skinfolds, and physical activity level. The magnitude and strength of the relationship were greater in women than in men. A negative interaction between ethanol intake and smoking status was evident. Linear regression coefficients in men were 0.29 sec to heart rate 130/ml ethanol/day in nonsmokers and -0.06 sec to heart rate 130/ml ethanol/day in smokers. Linear regression coefficients in women were 1.07 sec to heart rate 130/ml ethanol/day in nonsmokers and 0.23 sec to heart rate 130/ml ethanol/day in smokers. Men and women who smoked showed 31 sec longer time to heart rate 130, regardless of ethanol intake. Mean daily ethanol intake was positively associated with duration of treadmill testing in women, but weakly associated with duration in men. These results show increased physical fitness as ethanol intake increased in women and nonsmoking men and mildly decreased physical fitness as ethanol consumption increases among men who smoke.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic ethanol consumption affects cholinoceptor- and purinoceptor-mediated contractions of the isolated rat bladder

Isolated bladder strips from 12-week ethanol-fed, pair-fed and control adult male rats were investigated. Contractile responses to carbachol (CCh; 0.1-300 microM) were statistically significantly potentiated in the ethanol-fed group compared to pair-fed and control. Contractions to beta,gamma-methylene ATP (beta,gamma-MeATP; 1-300 microM) were statistically significantly potentiated in the ethanol-fed group at the highest concentration tested (300 microM). Neurogenic contractions (0.5-32 pps) from the ethanol-fed group in the absence of atropine and after desensitisation by alpha,beta-methylene ATP (alpha,beta-MeATP; 3 microM), were significantly potentiated compared to the pair-fed and control groups; in the presence of atropine (1 microM), neurogenic contractions were significantly augmented at the higher frequencies. It is concluded that chronic ethanol treatment affects both cholinoceptor- and purinoceptor-mediated contractions of the rat bladder.

Effect of acute ethanol ingestion on orthostatic vital signs

STUDY OBJECTIVE

To determine the effect of acute ethanol intoxication on the results of orthostatic tilt testing.

DESIGN

Prospective, randomized crossover study. Subjects received ethanol (1.1 gm/kg) or an equal volume of water added to nonalcoholic beer. Orthostatic vital signs, ethanol concentration, and relative volume status were checked initially and hourly for 8 hours.

PARTICIPANTS

Twenty healthy human volunteers, 10 men, and 10 women.

RESULTS

Peak ethanol concentration was 116 +/- 18 mg/dL (mean +/- SD) 1 hour after ingestion. ANOVA for repeated measures revealed a significant difference in orthostatic pulse change and relative volume deficit between the ethanol and placebo groups (P < .05). Post hoc testing revealed significant differences between the two groups at two, five, seven and eight hours post ingestion for pulse change, and two to eight hours for volume status (Bonferroni's corrected t test, P < .0055). At 2 and 5 to 8 hours, there were significantly more positive tilt tests (+/- 30 beat/minute increase) in the ethanol group than in the placebo group (P < .05). Starting at 2 hours, the ethanol group had a statistically significant relative fluid deficit averaging .5 L by 3 hours. There was no difference in postural blood pressure changes between the two groups.

CONCLUSION

In healthy volunteers, ethanol intoxication resulted in exaggerated postural pulse changes and in a greater proportion of positive orthostatic tilt test results than in a placebo group. These changes were accompanied by significant relative fluid deficits.

Cardiovascular effects of cocaine in humans: laboratory studies

Studies in which healthy, carefully screened, experienced cocaine users receive cocaine under controlled laboratory conditions, although often overlooked by the medical community, are an excellent source of data on the cardiovascular effects of cocaine. Cocaine is generally self-administered in repeated-dose 'binges', and studies simulating this pattern provide interesting cardiovascular information, such as the selective development of acute tolerance or the unique effects of some drug combinations. Studies with intranasal, intravenous, and smoked cocaine all show that under conditions in which subjects are allowed to take cocaine repeatedly, heart rate generally returns to near baseline levels between doses despite gradually increasing cocaine blood levels. Blood pressure either shows the same pattern, or gradual increases with repeated dosing. Analyses of cardiovascular activity as a function of cocaine plasma level indicate the rapid development of acute (i.e., within session) tolerance to cocaine. Cocaine self-administration often occurs in the presence of behavioral stressors, or in combination with other drugs of abuse or cocaine abuse treatment medications. Performance of a behaviorally-demanding task increases heart rate and blood pressure. When cocaine is taken prior to task performance larger increases in heart rate are observed than with either drug or task alone. An unexpected cardiovascular interaction was observed in subjects who inhaled cocaine and drank ethanol-containing beverages. This combination resulted in heart rate increases that were significantly larger than observed with either drug alone. Combinations of i.v. cocaine and smoked marijuana also increased heart rate above levels seen with either drug alone. A single intravenous dose of cocaine and morphine in combination, however, produced cardiovascular effects similar to those produced by cocaine alone. The effects of these drug combinations on blood pressure were often equal to the effect of one drug alone. Since cocaine is frequently taken in combination with potential treatment drugs, these interactions can be assessed under controlled settings prior to large-scale treatment studies. For instance, maintenance on the antidepressant desipramine increased baseline heart rate and diastolic pressure. Cocaine administration engendered increases in heart rate and blood pressure above the desipramine-elevated baselines. Clearly, drug interactions can have unexpected cardiovascular effects, and laboratory studies provide a controlled setting for understanding and studying these interactions.

Autonomic neurotoxicity of alcohol assessed by heart rate variability

Measurement of heart rate variability (CVR-R) provides a promising approach for evaluation of the autonomic nervous function. Specifically, high- and low-frequency component coefficients of variation of the CVR-R (C-CVHF and C-CVLF), computed from component spectral powers by autoregressive spectral and component analyses, are inferred to reflect parasympathetic and sympathetic activities, respectively. To assess the acute and chronic effects of alcohol on parasympathetic and sympathetic activities, ECGs in the supine posture were obtained in 11 male healthy volunteers, and in 23 male patients with severe alcoholic dependency together with the same number of age-matched healthy men. Significant changes in the CVR-R and heart rate were found 1 h after ethanol intake in the volunteers; also, the 1-h alteration in heart rate after intake was inversely correlated with that in the C-CVHF. The CVR-R, C-CVHF and C-CVLF were significantly depressed in the alcoholics compared to the matched controls. In the alcoholics, the age-adjusted correlation coefficients between not only the CVR-R but also C-CVHF and heart rate were negatively significant. These data suggest that acute and habitual intake of alcohol affects cardiac autonomic functions including sympathetic and parasympathetic activities; and, increase of heart rate in relation to alcohol, at least in alcoholics, seems to occur through reducing the parasympathetic activity.

Concurrent cocaine-ethanol ingestion in humans: pharmacology, physiology, behavior, and the role of cocaethylene

Simultaneous abuse of cocaine and ethanol is a common occurrence. Cocaethylene, the ethyl ester of benzoylecgonine, has been detected in the urine of patients reporting concurrent use of cocaine and ethanol, and high levels have been found in the blood of victims of fatal drug overdose. This placebo-controlled, double-blind study examined the pharmacokinetic, physiologic, and behavioral effects of dual cocaine and ethanol administration in humans (n = 6). Cocaethylene was found in the plasma only after administration of both cocaine and ethanol, and appeared to be eliminated more slowly than cocaine. Plasma cocaine concentrations were significantly higher during cocaine/ethanol administration. Euphorigenic effects were both enhanced and prolonged, and heart rate was significantly increased, following cocaine/ethanol administration as compared to administration of cocaine or ethanol alone.

Lifelong ethanol consumption enhances the age-related changes in rat sympathetic neurons

The effects of aging and chronic ethanol administration on the histochemical and morphometric features of rat superior cervical ganglion were studied in a rat strain selected for voluntary alcohol consumption. Ethanol was administered to the experimental group ad libitum (10% v/v in drinking water) from 3 months to 28 months of age, the average ethanol intake being 6.4-5.4 g/kg per day. The sympathetic neurons of the ethanol consuming rats showed several signs of enhanced degeneration, e.g. decreased neuronal packing density, increased amount of age-pigment and decreased intensity of catecholamine histofluorescence and tyrosine hydroxylase immunoreactivity. The results may indicate a selective vulnerability of peripheral sympathetic neurons rather than a universal accelerated aging due to chronic ethanol exposure.

Physical exercise after alcohol intake: effect on plasma catecholamines and lymphocytic beta-adrenergic receptors

The combined effects of alcohol intoxication and intense physical exercise on the adrenergic system were studied in eight healthy male volunteers. Ethanol (0.8 g/kg body weight) was administered perorally to bring about a mean serum concentration of 21 mmol/liter (0.1%); each subject also participated in an identical control session without alcohol. Acute alcohol intake alone did not change the concentrations of plasma adrenaline or noradrenaline or the density, affinity, and functioning (ability to mediate catecholamine-stimulated production of cAMP) of lymphocytic beta-adrenergic receptors. In contrast, acute ergometer exercise brought about an approximately 10-fold increase of plasma adrenaline and noradrenaline concentrations, a 2- to 3-fold increase of beta-adrenergic receptor density and an enhancement of isoproterenol-stimulated cAMP production. Alcohol intake immediately before the ergometer exercise did not modify these changes. In conclusion, acute physical exercise activates the human adrenergic system, with an increase of both plasma catecholamines and lymphocytic beta-adrenergic receptors. Moderate alcohol intoxication does not affect exercise-induced alterations of these parameters.

Diagnostic evaluation of syncope

Syncope is a common medical problem and is caused by a wide variety of diseases ranging from physiologic derangements with few consequences to conditions that may be immediately life-threatening. Because of the large differential diagnosis, many diagnostic tests are available for its evaluation. However, a cause of syncope is not established in 38% to 47% of patients despite these tests. In those patients in whom a diagnosis can be assigned, the history and physical examination identify a potential cause in 49% to 85%. Furthermore, in 8% of additional patients, history and physical examination are suggestive of causes that need confirmation by specific tests. Routine blood tests rarely yield diagnostically helpful information. In those patients in whom a potential cause for syncope is identified, arrhythmias are diagnosed by electrocardiogram in 2% to 11% of patients, cardiac monitoring in 3% to 27% (telemetry or Holter), stress test in less than 1%, carotid massage in less than 1%, and electrophysiologic studies in less than 3%. Diagnosis of arrhythmias as a cause of syncope is problematic because symptomatic correlation during electrocardiographic monitoring is rarely found (approximately 4%), and as a result, there is no uniform agreement on diagnostic criteria for abnormalities. Similar problems exist in the use of electrophysiologic studies. Upright tilt testing and psychiatric examination may be useful in evaluation of recurrent syncope of unknown cause in patients without organic heart disease. Based on the results of recent studies, strategies for evaluation of patients with syncope are possible that utilize selective and goal-directed diagnostic testing.

Urinary catecholamines in hyperthermia-related deaths

A group of five hyperthermia-related deaths is presented in which urinary noradrenaline (NA) concentrations were elevated (172.1 +/- 119.4 ng/ml) compared with a control group of rapid violent deaths (43.7 +/- 26.1 ng/ml). Urinary adrenaline (A) concentrations were not elevated in the hyperthermia cases, nor were there any significant differences in urinary dopamine (DA) concentrations between the two groups. All except one of the hyperthermia victims were under the influence of ethanol. It is suggested that a combination of heat stress and ethanol consumption was responsible for the elevated urinary NA in the hyperthermia cases, reflecting increased sympathetic nervous system activity. A combination of high urinary NA with low A seems to be characteristic of hyperthermia fatalities, in contrast to hypothermia deaths, where both NA and A are usually elevated.

Membrane actions of ethanol on rabbit sino-atrial node studied by voltage clamp method

Electrophysiological effects of ethanol on rabbit sino-atrial node were studied by means of the double-microelectrode voltage clamp method. In spontaneously beating preparations, ethanol (above 1%) decreased the maximum rate of depolarization of the action potential. Furthermore, 3% ethanol produced a significant decrease in the action potential amplitude, the action potential duration at 50% repolarization and the rate of the diastolic depolarization. Of the current systems, voltage clamp studies showed that ethanol reduced the slow inward current, the time-dependent potassium outward current and the hyperpolarization activated inward current. These observations indicate that ethanol does not have an effect on a single current system, but directly modifies the spontaneous discharge of sino-atrial node pacemaker cells due to a reduction of the time-dependent current systems.

Effect of acute ethanol intake and hangover on the levels of plasma and urinary catecholamines and lymphocytic beta-adrenergic receptors

To determine whether acute ethanol administration affects the function of the adrenergic system the concentrations of plasma catecholamines and cyclic AMP (cAMP), the level of lymphocytic beta-receptors, the concentration of basal and isoproterenol-stimulated lymphocytic cAMP and the excretion of urinary catecholamine metabolites were studied in six healthy men. These parameters were also measured during the hangover, both under resting condition and during an anaerobic ergometer exercise. Acute intake of ethanol (1.5 g/kg body weight) had no statistically significant effect either on plasma adrenaline and noradrenaline concentrations or beta-adrenergic receptor levels. Ethanol consumption did neither change the urinary excretion of catecholamine metabolites (homovanillic acid, normetanephrine, metanephrine, and 3-methoxyhydroxymandelic acid). Exercise was associated with a 6-10-fold elevation in plasma adrenaline and noradrenaline concentrations and with a two- to threefold elevation on beta-adrenergic receptor levels. This effect of exercise was not modified by preceding alcohol intake and resulting hangover. These preliminary findings suggest that acute alcohol intake does not significantly alter the concentration and functioning of human beta-adrenergic receptors.