Adrenoceptors on blood cells in patients with essential hypertension before and after mental stress.

The effect of mental arithmetic (MA) on alpha 2- and beta 2-adrenoceptors on platelets and lymphocytes, respectively, and on plasma catecholamines was studied in normotensive (NT) and essential hypertensive (HT) subjects. There were no significant differences in responses of blood pressure, forearm blood flow (FBF) and heart rate to MA between the two groups. Baseline values and changes in adrenaline and noradrenaline levels during MA were similar in NT and HT. Alpha 2-adrenoceptor density and antagonist affinity did not differ between NT and HT and was not influenced by MA. Baseline values of beta 2-adrenoceptor density also did not differ between NT and HT and increased similarly after MA in both groups. Antagonist affinity to the beta 2-adrenoceptors under baseline conditions was lower in HT and did not change during MA in either group. Our results indicate that there are no differences between NT and HT in alpha 2- and beta 2-adrenoceptor density, either under baseline conditions or after mental stress.

The effect of (induced) maternal emotions on fetal behaviour: a controlled study.

In ten healthy near-term pregnant women the effect of induced maternal emotions on fetal motor behaviour was studied. Emotions were induced by showing a film of a normal delivery. Fetal behaviour was recorded by means of real-time ultrasound observations of general movements and eye movements and by fetal heart rate monitoring. The observations had a duration of 2 h. The data were compared with those obtained during a 2-h control period, which took place the day before (n = 5) or after the study period (n = 5). Maternal emotions (induced) were measured by means of psychological tests. No effects on fetal motor activity or on behavioural state organization could be found as a result of this film. There was, however, a significant positive correlation (P less than 0.01) between the mean level of anxiety of the women and the motor activity of the fetuses.

Trends in Poland in space psychology research.

This paper discusses the basic directions of research carried out in Poland during the years 1981-86 within the Polish Academy of Science project 06.7. The subject matter concerns: individual and situational determinants of human functioning in stress conditions; functioning of a human in extreme conditions; and load imposition through activities requiring risk-taking decisions.

Stress and cognitive functioning in sport.

This paper considers the relationship between stress and cognitive functioning and discusses some of the concepts and methods that may be adopted to examine the relationship between stress and sports performance. It considers only that literature that may be relevant to, or furthers, the understanding of sports performance under competitive stress. One of the most popular approaches has been to explain the relationship in terms of the unidimensional inverted-U hypothesis. The validity of this approach to explaining sports performances in specific situations is discussed and it is generally concluded that the inverted-U hypothesis is too vague and simplistic. The discussion considers multidimensional approaches and discusses the suitability and implications of some more recent and more complex models of stress and performance which are now available in the psychological literature. It is concluded that the relationship between stress and sports performance is an extremely complex one and involves the interaction between the nature of the stressor, the cognitive demands of the task being performed and the psychological characteristics of the individuals performing it.

Effects of aminophylline on behaviorally induced coronary blood flow increases.

It has been proposed that adenosine is a metabolic vasodilator that matches myocardial oxygen supply to demand by regulating coronary blood flow. In the present study, the adenosine antagonist aminophylline (Am) was used to evaluate the role adenosine plays in the coronary blood flow increase elicited by a controlled aversive stress, namely, classical aversive conditioning (a 30-s tone reinforced with a 1-s shock). Fifteen mongrel dogs were chronically instrumented to measure left circumflex coronary blood flow (CBF), left ventricular pressure (LVP), and heart rate. Am significantly (P greater than 0.01) attenuated the CBF response to the aversive stress without affecting the prestress levels (pre-Am control 40.9 +/- 2.4, peak 64.6 +/- 3.3 ml/min; post-Am control 41.7 +/- 2.2, peak 55.0 +/- 2.5 ml/min). The maximal CBF increase was reduced by 38.9 +/- 6.7% when compared with the control (no drug) condition. In a similar manner, neither heart rate nor LVP was affected by Am. However, Am significantly increased prestress level of first derivative of left ventricular pressure with reference to time [LV dP/dt] (pre-Am control 3,793.5 +/- 289.8 and Am 4,599.6 +/- 331.2 mmHg/s, respectively). These data suggest that adenosine contributes significantly to the regulation of CBF during a controlled emotional stress.

Estudio experimental de la depresión por estrés social / Experimental study of depression by social stress

Se estudió experimentalmente la depresión reactiva en monos inducida por conflitos sociales. Con este fin se usó como modelo la formación de nuevos grupos con animales desconocidos entre sí, ya que este procedimiento induce estrés asociado a un cuadro somático y conductual de depresión emocional. Se emplearon dos grupos de monos (Cercopithecus aethiops) que se formaron simultáneamente en jaulas gemelas y contiguas, con igual composición social (cuatro hembras y un macho adulto y cuatro juveniles de ambos sexos en cada grupo). La conducta social se registró diariamente durante una hora en cada grupo y se analizaron las conductas afiliativas de juntarse, espulgarse, el juego y la conducta sexual. Las conductas de rechazo estudiadas fueron los desplazamientos, las fintas, y los ataques. Durante las primeras cinco semanas después de la formación murieron dos hembras adultas y dos juveniles en cada grupo. Dos de los juveniles murieron el día de la formación a consecuencia de las heridas recibidas y los dos restantes murieron de neumonía unos días después. En cambio las necropsias de las hembras adultas mostraron hemorragias petequiales e hipertrofia de las glándulas suprarrenales y en un caso úlceras gástricas. Los animales sobrevivientes se continuaron estudiando durante dos meses más con el propósito de permitir la consolidación de lazos afiliativos y posteriormente ambos grupos se unieron en uno solo. La conducta social de las hembras deprimidas que murieron se comparó con la de las hembras que lograron adaptarse socialmente y por tanto sobrevivir. Las diferencias más significativas ocurrieron en la conducta afiliativa más frecuente (juntarse con otro u otros) así como en la conducta de rechazo más frecuente (los desplazamientos). El grupo de hembras que murieron se juntó primordialmente con los juveniles mostrando frecuenta progresivamente decrecientes...

Cognitive stress and cardiovascular reactivity. II. Relationship to atherosclerosis, arrhythmias, and cognitive control.

This is the second of a two-part series on the effects of cognitive stress on cardiovascular disease. This paper reviews the relationship between cognitive stress and cardiovascular reactivity as it relates to the development of atherosclerosis and arrhythmias. In addition, the moderation of cardiovascular reactivity by the opportunity to exercise control over the stressor is discussed. The findings may be summarized as follows. First, recent animal work has suggested that the magnitude of heart rate change in the presence of a conditioned aversive stimulus is positively correlated with the extent of coronary atherosclerosis under diets high and low in atherogenic potential. Second, cardiovascular reactivity in humans may be related to several factors that could have an influence on the pathogenesis of atherosclerosis. These factors include: increased beta-adrenergic driving, increased shearing force on the intimal lining of the vessels, changes in pulsatile flow and the subsequent smooth muscle reparatory process. Cognitive (psychological) stress has also been related to ST segment depression, rate-pressure product changes, and changes in cardiac contractility. Animal studies have shown that the susceptibility to ventricular fibrillation may be enhanced by the presence of a conditioned aversive stimulus and may be reduced through adaptation to the aversive environment. The balance between sympathetic and parasympathetic influences on the myocardium may also play a critical role in the susceptibility of an already diseased heart to succumb to fatal arrhythmias during a behavioral stressor. Finally, studies in which subjects may exercise some control over an aversive stimulus suggest that cardiovascular reactivity may be pronounced and sustained in situations requiring frequent adjustment to changes in the criteria for successful performance, and/or the presence of positive incentives.

Childhood near-death experiences.

We nonselectively interviewed 11 patients aged 3 through 16 years who had survived critical illnesses, including cardiac arrests and profound comas. Any memory of a time they were unconscious was considered to be a near-death experience (NDE) and was recorded. Seven of these children had memories that included being out of the physical body (six patients), entering darkness (five patients), being in a tunnel (four patients), and deciding to return to the body (three patients). We also interviewed 29 age-matched survivors of illnesses that required intubation, narcotics, benzodiazepines, and admission to an intensive care unit. None of them had any memories of the time they were unconscious. In our study population, NDEs were clearly associated with surviving a critical illness. The elements of NDEs reported are similar to those previously described in adults. No children described elements of depersonalization as part of their NDEs. A core NDE, triggered by the process of dying or resuscitation efforts, may be a natural developmental experience. We present a neurophysiologic hypothesis as to the cause of NDEs.

Cerebral lateralization of emotional reaction in rats during different emotional pressures.

Interhemispheric asymmetry of the "emotional resonance" reaction with a varied degree of emotional action was investigated in rats. Hemisphere inactivation was carried out by means of potassium spreading depression. "Emotional resonance" in rats has been shown to possess hemisphere asymmetry. This asymmetry is dynamic and changes depending upon the conditions under which the reflex is worked out. With equal illumination of both the preferred and the nonpreferred chamber and using "recipients" and "victims" of the same sex, left hemisphere dominance was found in males in carrying out the reaction. With a tenfold difference in chamber illumination and testing animals of the same sex, the right hemisphere dominated in rats working out the reflex quickly, whereas in those working out the reflex more slowly it was the left one. In using "victims" and "recipients" of the opposite sexes and the same darkening of the preferred chamber the right hemisphere dominated in carrying out "emotional resonance." "Emotional resonance" in lactating females to the cry of their pups was also characterized by right hemisphere dominance. Thus, dependence between the force of emotion and the direction of "emotional resonance" lateralization in rats was shown. The interhemispheric asymmetry observed was more expressed in males than in females.

Effects of 50 Hz electric currents on mood and verbal reasoning skills.

Seventy-six male volunteers were studied in a crossover trial to assess the impact on the central system of electric currents such as might be induced by exposure to an intense power frequency electric field. Currents totalling 500 microamperes (50 Hz) were passed through electrodes attached to the head, upper arms, and feet, simulating exposure of and average man to a vertical electric field of about 36 kV/m. Exposure was continuous for a single day (5.5 hours) and the experiment was based on a double blind, counterbalanced, within subject design. A series of psychological tests examining self reports of both stress and arousal (mood checklist) and performance tests of memory, attention, and verbal skills were administered. Although the double blind conditions were compromised to some extent by reported sensations at electrode sites, the duration of these sensations was small in relation to the overall exposure or sham exposure time and did not interact with the effects apparently associated with exposure that were found. No significant difference between the exposed and sham-exposed groups was found on the first day, but on the second day the sham exposed group felt more aroused at the end of the day and their response times had improved more on the complex problems of a syntactic reasoning test. No exposure effects were apparent in self reports of stress or in performance in a semantic reasoning test, although both showed some influence of sensations. Interpretation of the exposure effects is complicated by their apparent restriction of the second test day, which may indicate some type of state dependent transfer phenomenon.

Biochemical and behavioral correlates of chronic stress: effects of tricyclic antidepressants.

Using a chronic stress model of depression, the biochemical, hormonal, and neurochemical effects of chronic stress were determined in male CD-1 mice. The effects of chronic administration of three tricyclic antidepressants (TCA): chlorimipramine, amitriptyline and desmethylimipramine, as well as fluoxetine, a specific serotonin uptake inhibitor, were also evaluated. Exposure to acute noise/light stress dramatically increased motor activity (behavioral activation) in comparison with basal (unstressed) activity. However, animals with a history of chronic stress exhibited reduced basal activity levels as well as a decreased behavioral activation response to acute stress. There was also exaggerated corticosterone (CS) responding in both of these behavioral test situations attributable to prior chronic stress exposure. Chronic treatment with any of the TCAs significantly restored the behavioral activation response to acute stress and normalized CS responding in chronically stressed animals. Chronic fluoxetine treatment was ineffective. In chronically stressed, but behaviorally untested (quiescent) mice, there were no changes in CS levels, but norepinephrine (NE) and 5-hydroxyindoleacetic acid (5-HIAA) levels were increased. However, chronically stressed mice tested for basal motor activity showed large NE decreases, while those receiving acute stress exposure prior to testing showed large NE decreases and further 5-HIAA increases. There were no alterations on neurochemical parameters due to any drug treatment which could be correlated with a possible mechanism for their efficacy, although evidence suggested NE involvement. It was further proposed that the chronic stress paradigm induced conditioned neuroendocrine and neurochemical responses.

A correlation analysis between pulse transit time and instantaneous blood pressure measured indirectly by the vascular unloading method.

Linear correlation coefficients (r) between pulse transit time (PTT) and blood pressure (BP) were evaluated on within-subject by within-condition level. Beat-to-beat systolic and diastolic BP was measured noninvasively using the vascular unloading technique (Yamakoshi, Shimazu and Togawa, 1980). PTT was determined from the time interval between the R-wave of ECG and the peak of the finger pulse wave. Five male subjects underwent a 2 min resting (RE), a 1 min cold pressor test (CP), eight 15 sec anagram tests (AN), and another 1 min CP. Significant r values were most frequently obtained for systolic BP and PTT in the RE condition. Under the CP or AN conditions, no consistent tendencies were observed. It was suggested that none of the r values are sufficiently high to warrant the use of PTT as an alternative index of BP. Some factors lowering the r values were discussed.

Continuous social defeat induces an increase of endogenous opioids in discrete brain areas of the mongolian gerbil.

Dyads of a victor and a loser of mongolian gerbils (Meriones unguiculatus) coexisted for seven days; isolated animals served as a further experimental group. beta-Endorphin, Met-enkephalin and dynorphin were measured in several brain areas and in the anterior and neurointermediate pituitary. beta-Endorphin and Met-enkephalin were increased in the amygdala of defeated as compared to victorious animals. Met-enkephalin in the hypothalamus and in the striatum were lower in isolated than in coexisting gerbils. Coexistence decreased beta-endorphin in the amygdala and in the hypothalamus as compared to isolation. The results provide biochemical evidence for the role of central endogenous opioid-peptide systems in the physiology of victory and defeat. Dynorphin showed no variation with social conflict and social status.

Some aspects of physiology and pharmacology of endogenous opioid peptides.

The review, based largely on our own results describes the present state of knowledge of some aspects of opioid peptides and their physiological role. Studies on the effect of opioid peptides and opiates on brain function and the changes of brain level of endogenous opioids under various conditions have demonstrated, among others, the role of opioids in stress and stress-induced analgesia, the involvement of various opioid receptors in spinal mechanisms of analgesia, the inhibitory role of dynorphin in seizures in contrast to proconvulsant action of beta-endorphin system and mu receptor, and led to postulation of the role of beta-endorphin interaction with serotonin for ingestive behavior and a possible involvement of beta-endorphin system in the mechanism of action of antidepressant treatments.

[Behavior of free catecholamines in blood and urine of ambulance men and physicians during quick responses]. / Zum Verhalten der freien Katecholamine im Blut und Harn bei Sanitätern und Arzten während des Einsatzes.

Free urine adrenaline, noradrenaline, (additional free plasma catecholamines in the physicians), and blood lactate were determined in 11 ambulance men and 5 physicians to assess stress during medical service. Stress was evaluated employing a stress index, based on difficulties in driving, traffic, severity of injuries or illness. Emergency cases with seriously injured subjects or reanimation were judged to have a 4-fold higher stress index than routine cases where strong physiological or psychological stress was absent. Urine catecholamines and stress indices were estimated in 3-h intervals. The calculations were based on the stress induced catecholamine concentrations minus the basal excretion during the same 3-h interval. Urine adrenaline and noradrenaline in ambulance men and physicians correlated directly with the stress index, as well as the plasma catecholamines of the physicians. Lactate levels showed similar behaviour and a descriptive direct correlation with the plasma catecholamines. Urine adrenaline increased more--dependent on the stress index--than urine noradrenaline. This over-proportional adrenaline response may be an indicator for the additional psychological stress in emergency cases. Therefore physicians showed--based on the same stress index--a tendency to higher urine adrenaline excretion and blood lactate levels than the ambulance men, which might be the consequence of the overall responsibility of the physicians. Because of the observed catecholamine responses during medical service, coronary insufficiency or hypertension might be contra-indications for participation in the medical service; regular clinical investigations including ergometric tests are advisable.