Retention of orienting reaction habituation in chronic alcoholics

A polygraphic study on resistance to habituation of the somatic (EMG), autonomic (finger plethysmogram, galvanic skin reaction, respiration) and EEG (acoustic-evoked potential and EEG-blocking reaction) components of the orienting reaction, elicited by a repetitive auditory stimulus during successive (weekly) sessions was performed in 67 chronic alcoholics and in 70 matched normal subjects (control group). The study showed significant retention disturbances of orienting reaction habituation (i.e., of learning), or the "saving" of stimulations, achieved from one session to the other to obtain the habituation criterion, the savings being less in alcoholics than in control subjects. The severity of habituation retention disturbances depended on patients' ages, types of alcoholism, alcohol consumption intensity and chronicity, as well as the type of resting EEG.     

Orienting reaction in patients with multiple sclerosis

A polygraphic study of the somatic (EMG), autonomic (finger plethysmogram, galvanic skin reaction, respiration, pulse, and EEG (acoustic-evoked potential and EEG-blocking reaction) components of the orienting reaction elicited by an auditory stimulus was performed in 71 patients with multiple sclerosis and in 74 matched normal subjects (control group). The study showed a significantly less intense orienting reaction in patients with multiple sclerosis than in control normal subjects. The severity of this responsiveness disturbance depended on the patients' age at symptom onset, major symptom types on admission, and the relapse frequency. The orienting reaction changes found in patients with multiple sclerosis may be ascribed to the diffuse demyelinating lesions in the nervous system of these patients, which generate, apart from the so polymorphous clinical manifestations of this disease, also important responsiveness disturbances.     

Cultured lymphocytes in chronic alcoholics

Lymphocytes were isolated from the peripheral blood of 80 chronic alcoholics without an evident liver damage and filled up with 4 different mitogens. The DNA synthesis was investigated by means of the 3H thymidine incorporation rate. They were referred to a group of 15 healthy test persons. An increased proliferation rate of B-lymphocytes could be demonstrated, whereas there was no evidence for a change in the stimulatibility of T-lymphocytes. It was only the direct impact of ethyl alcohol on lymphocytes that produced a significant decrease in the ability of T-cell reactivity, whereas a further increase of stimulatibility could be observed in B-cells. Our findings allow the conclusion to be drawn that an immediate toxic impact of ethanol on lymphocytes can be identified in chronic alcoholics without manifest liver damage.     

Blood glucose in intoxicated chronic alcoholics.

Chronic alcoholics may present with hyperglycemia or hypoglycemia. Because alcohol induces glycogenolysis, chronic alcoholics usually have higher blood glucose values than do nonalcoholic subjects. In a prospective study of blood glucose concentration in 201 chronic alcoholics, blood alcohol concentration, sex, weight, type of beverage consumed and time since last eating were not generally associated with lower blood glucose values. The infrequency of hypoglycemia in ambulatory chronic alcoholics may reflect the relatively ready availability of hostels, detoxification centres and hospitals in large cities. It is, however, important to be aware of the possible occurrence of hypoglycemia in chronic alcoholics, particularly when community facilities for the chronic alcoholic are not available.     

Hair zinc and copper in chronic alcoholics

Chronic alcoholics frequently show associated malnutrition. Both ethanol and malnutrition exert profound changes on zinc and copper metabolism. In this study, we found higher hair zinc and copper values in 43 male alcoholics than in 39 controls. Hair copper was significantly related to the amount of ethanol consumed, whereas hair zinc was higher in consumers of distilled beverages. No relation was observed between hair zinc and copper and nutritional status, kind of diet consumed, style of life, and liver cirrhosis. Consequently, hair zinc and copper levels are related only with alcohol intake.     

DNA-repair capacity and lipid peroxidation in chronic alcoholics

The possible impact of long-term overexposure to ethanol was studied in a group of chronic alcoholics in the psychiatric hospital. The level of DNA methylation and unscheduled DNA synthesis (UDS) induced by N-methyl-N-nitrosourea (MNU) in lymphocytes and lipid peroxidation (LPO) in plasma were used as markers of injury caused by alcohol abuse. The data were correlated with plasma levels of some natural antioxidants (vitamins A, C and E) and vitamin B12. The following results were obtained. The degree of DNA methylation by MNU in lymphocytes was the same in the exposed and control groups under our experimental conditions. The DNA excision-repair capacity of lymphocytes measured as UDS was decreased in alcoholics (p less than 0.01) and LPO in plasma was significantly higher (p less than 0.01) as a consequence of alcohol overconsumption. By the simple regression method, a correlation was found between LPO and vitamin C levels (LPO = -0.078 x vit. C + 1.9; p less than 0.05) and between UDS and LPO values (UDS = -0.384 x LPO + 4.1; p less than 0.05). These results support the hypothesis of a connection of cell membrane status and DNA damage and repair and the possible role of active oxygen species in cell damage caused by ethanol.     

The metabolic response to exercise in chronic alcoholics

The metabolic response to steady exercise was studied in six chronic alcoholics and six normal control subjects. Higher concentrations of lactated and pyruvate were observed in the alcoholics during exercise and they also developed post-exercise ketosis. These changes were probably not due to reduced fitness of the alcoholics as the heart rates of both groups were similar. Alcoholics had lower levels of growth hormone during exercise compared with the controls suggesting that chronic alcohol consumption has a depressor effect on pathways regulating the release of growth hormone.     

Orienting reaction, organizing for action, and emotional processes

In the first half of the sixties, general notions were formulated concerning the functional role of the orienting reaction (OR) in adaptive activity, its elicitation and habituation. These notions included the following: a) The OR is elicited only by significant changes in a situation. This implies that OR elicitation is preceded by brain processes (usually unconscious) pertaining to the evaluation of the significance of changes according to an existing hierarchy of motivations, attitudes, and goals. Therefore, the OR is of an active (vs. reactive) nature, i.e., is inevitably determined by internal factors of brain activity. b) The OR is not a unitary reaction, but a complex polyfunctional activity, different aspects of which are reflected in different OR components which can be modified rather independently. c) The OR represents the processes of organizing new (non-standard) actions: sensory, motor, or intellectual. OR habituation is a manifestation of attenuation of the active control of an action, and an increase in its automation. Thus, the emphasis in understanding the OR has shifted from a predominantly "sensualistic" platform to a predominantly "actualistic" one. In recent experiments, the role of emotional processes in the elicitation and habituation of components of the OR has been analyzed. Complex relations between the GSR and anxiety were found in a study of patients with acute alcohol withdrawal syndrome treated with different psychopharmacological agents. The study of auditory evoked potential habituation in depressive patients has shown the emotional state influence on sensory aspects of the OR with the participation of the OR brain mechanisms in perceptual defense.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clastogenic effect of ethanol in chronic and abstinent alcoholics

Alcoholism is one of the main causes of damage for human health, being relevant to study the induction of chromosomal aberrations (CA) by ethanol, and to investigate the individual susceptibility to diseases caused by alcoholism. A cytogenetic study was performed in human peripheral blood lymphocytes of 29 heavy chronic alcoholics, 11 alcoholics in abstinence, and 10 controls. The values of the chromosomal aberrations, mitotic indexes (MI) and proliferation indexes (PI) were determined. A molecular cytogenetic study was also carried out using fluorescence in situ hybridization (FISH) method with DNA library probes for chromosomes 1, 3 and 6, in lymphocytes from chronic alcoholic individuals in comparison with a control group. The results showed that the CA frequencies for chronic alcoholics (5.15 CA/100 cells) and alcoholics in abstinence (3.87 CA/100 cells) were higher than those obtained for control individuals (1.72 CA/100 cells). The mean translocation frequencies (equivalent to the genome) were calculated for six chronic alcoholics (0.267 translocations/100 cells) and six alcoholics in abstinence (0.167 translocations/100 cells), whose values were significantly higher than those observed for six control individuals (0.067 translocations/100 cells). The CA frequencies were not statistically different when smoker and non-smoker alcoholics were compared, indicating that although the smoking habit had significantly increased (four-fold) the CA frequency in healthy control individuals, a lack of interaction effect was observed within the group of alcoholics when smokers and non-smokers were compared. The CA frequencies presented by alcoholics in abstinence were similar to those obtained for chronic alcoholics. Therefore, chronic ethanol intoxication can lead to chromosome damage and disturbances in the metabolism of endogenous and exogenous compounds, which may persist for a long time, and constitute a relevant factor of risk for the development of neoplasias.     

Clastogenic effect of ethanol in chronic and abstinent alcoholics

Alcoholism is one of the main causes of damage for human health, being relevant to study the induction of chromosomal aberrations (CA) by ethanol, and to investigate the individual susceptibility to diseases caused by alcoholism. A cytogenetic study was performed in human peripheral blood lymphocytes of 29 heavy chronic alcoholics, 11 alcoholics in abstinence, and 10 controls. The values of the chromosomal aberrations, mitotic indexes (MI) and proliferation indexes (PI) were determined. A molecular cytogenetic study was also carried out using fluorescence in situ hybridization (FISH) method with DNA library probes for chromosomes 1, 3 and 6, in lymphocytes from chronic alcoholic individuals in comparison with a control group. The results showed that the CA frequencies for chronic alcoholics (5.15 CA/100 cells) and alcoholics in abstinence (3.87 CA/100 cells) were higher than those obtained for control individuals (1.72 CA/100 cells). The mean translocation frequencies (equivalent to the genome) were calculated for six chronic alcoholics (0.267 translocations/100 cells) and six alcoholics in abstinence (0.167 translocations/100 cells), whose values were significantly higher than those observed for six control individuals (0.067 translocations/100 cells). The CA frequencies were not statistically different when smoker and non-smoker alcoholics were compared, indicating that although the smoking habit had significantly increased (four-fold) the CA frequency in healthy control individuals, a lack of interaction effect was observed within the group of alcoholics when smokers and non-smokers were compared. The CA frequencies presented by alcoholics in abstinence were similar to those obtained for chronic alcoholics. Therefore, chronic ethanol intoxication can lead to chromosome damage and disturbances in the metabolism of endogenous and exogenous compounds, which may persist for a long time, and constitute a relevant factor of risk for the development of neoplasias.     

Decrease in excitability of LG following habituation of the crayfish escape reaction

Crayfish escapes from threatening stimuli to the abdomen by tailflipping upwards and forwards. This lateral giant (LG)-mediated escape reaction habituates readily upon repetitive sensory stimulation. Using an isolated abdominal nerve cord preparation, we have analyzed the change in LG activity by applying additional sensory stimulation after different periods following habituation to characterize the retention of LG habituation. Results show that the LG mediated response habituates more quickly, but the retention time is shorter, as repetitive sensory stimulation is applied at progressively shorter inter-stimulus time intervals. The spike response of LG recovers quickly, within several minutes after habituation, but they fail to spike when an additional stimulus is applied after specific long periods following habituation. The critical period of the delay for this decrease in excitability of LG is dependent on the inter-stimulus time interval of the initial repetitive stimulus. As the inter-stimulus interval became longer, the delay needed for decrease in excitability became shorter. Furthermore, the local injection of 10^–6 mol l^–1 octopamine into the neuropil just following habituation promotes the achievement of decrease in excitability. No effects were observed when 10^–6 mol l^–1 serotonin and tyramine were injected. These results suggested octopamine promotes decrease in excitability of LG following habituation.     

Effects of vasopressin on the habituation of the orienting reaction in men

Effects of arginine-vasopressin (AVP) on the habituation of the orienting reaction and response to stimulus mismatch were investigated in a between-group design with 40 healthy male volunteers using skin conductance and heart rate responses as dependent measures. Twenty-one 1000 Hz tones of 90 dB(A) intensity and 2 s duration were presented with alternating intervals of 20 and 140 s. Stimulus mismatch responses were analyzed to the tones after the long intervals and to a change of the interval duration. The expected prevention of habituation as an indicator of a general stimulus-related increase of phasic arousal under AVP could not be confirmed. There were no differences between the AVP and the placebo group in the skin conductance and heart rate responses. The interval change did not provoke a dishabituation reaction, but responses to the tones after the long intervals were reliably enhanced. However, AVP did not increase the reaction to stimulus mismatch. It is concluded that autonomic indicators of the habituation of the OR remain unaffected by AVP.