Acta physiologica Scandinavica. Supplementum最新文献

While socio-epidemiologic studies documented impressive associations of indicators of chronic psychosocial stress with cardiovascular (c.v.) disease evidence on patho-physiologic processes is still limited. In this regard, the concept of heightened c.v. and hormonal reactivity (RE) to mental stress was proposed and explored. While this concept is a static one we suggest a more dynamic two-stage model of RE where recurrent high responsiveness (stage 1) in the long run results in attenuated, reduced maximal RE due to functional adaptation (stage 2). We present results of an indirect test of this hypothesis in a group of 68 healthy middle-aged men undergoing a modified Stroop Test: in men suffering from high chronic work stress in terms of effort-reward imbalance significantly reduced RE in heart rate, adrenaline and cortisol was found after adjusting for relevant confounders. In conclusion, results underscore the potential of linking sociological with physiological data in stress research.

This paper summarizes some of the highlights of our current social stress research in rodents as it was inspired by the work of Jim Henry. First, it is argued that social defeat can be considered as one of the most severe stressors among a number of laboratory stressful stimuli in terms of neuroendocrine activation. Moreover, the stress response induced by defeat in particular is characterized by a strong sympathetic dominance. Depending on the stress parameter, the stress response induced by a single social defeat may last from hours to days and weeks. As a long term consequence of a single defeat experience, the animal becomes sensitized to subsequent minor stressors. Finally, the importance of individual differences in coping style in relation to stress vulnerability is discussed.

In this article we summarize our work on the relationships between the social environment, behaviour and stress in guinea pigs. We confirm what Jim Henry predicted to be a general rule for all mammals including man 20 years ago: The individual's degree of social stress is related to the stability of the pre- and postnatal social environment in which it lives, to the amount of social support which it receives from bonding partners and to the social experiences which it has made during behavioural development.

Pigs can be characterised as resistant (R) or non-resistant (NR) at an early age (1 to 2 weeks) by means of a backtest. In the test the animal is put on its back and the number of bouts of resistance is used to characterise the animal. The test is performed twice with 1 week interval and only pigs that show a consistent response in both tests are classified as either R or NR pigs. On average eighty percent of a population can be classified by this test. R and NR pigs show consistent behavioural, physiological and immunological differences when tested in various challenge test in later life. The R pigs are more sympathetically dominated and showing an active coping style (fight/flight) as described in rats and mice. The NR pigs are more para-sympathetically dominated, resembling the passive coping style (conservation/withdrawal). In intensive husbandry, breeding sows are housed individually and often tethered. After long term tethering these sows show signs of chronic stress; overreaction of the sympathetic nervous system, hypercortisolaemia and disturbed behaviour. The most common disturbed behaviour found in tethered sows is stereotyped behaviour. Most sows develop stereotypies within 1 month after first tethering. Again great differences are found in the amount of stereotypies shown between sows. Some sows spent up to 80% of their active time on this behaviour while others hardly develop stereotypies. Sows showing high levels of stereotypies manage to counteract the sympathetic overreaction caused by the chronic stress of tethering as was shown by a decrease in heart rate during bouts of stereotyped behaviour. In this view stereotypies help the animal to cope with the averse situation of tethering. However, after 8 months of tethering stereotypies are no longer effectively attenuating heart rate. The effect of stereotypies is limited to the initial phase of chronic stress when the animal is striving to regain control. When chronic stress persists stereotypies get dissociated from their effect on the sympatho-adreno-medullary system and the animal loses control.

In his Instincts, Archetypes, and Symbols James P. Henry places physiological aspects of religious experience in the context of cultural anthropology and religious philosophy. His approach is Jungian. Of major concern is the liberation of the human mind from privatizations of goodness (privatio boni). Henry characterizes optimal natural conditions for a healthy psyche substantiated by physiological research.

Studies with male cynomolgus monkeys suggest that atherosclerosis is potentiated among individuals that are habitually successful in their aggressive encounters with social strangers, thereby retaining dominant social status in an unstable environment. Further, the increased risk of atherosclerosis experienced by such animals is related, in part, to the autonomic (sympathetic) adjustments they make while responding to the demands of retaining dominant status. These data provide clear support for the hypothesis that psychosocial factors influence disease pathogenesis via neuroendocrine mediation. Additionally, they provide initial evidence in favor of Jim Henry's suggestion that the pattern of neuroendocrine response to environmental challenge depends on the type and degree of control an animal can exert in such circumstances (Henry & Stephens 1977).

The acceleration fields in the vicinity of quietly moving prey are governed by the same mathematical equation as the bioelectric fields aquatic animals produce. Hence, to reach their prey, predatory fish may use the inertial sense organs of the inner ear in a similar fashion as sharks and rays use the electroreceptors, the ampullae of Lorenzini. Besides the acceleration fields, predatory fish may detect the velocity fields of the prey, responding to the accelerations the inner ear receives from the spatial differences in the velocity experienced over time due to the relative motion between predator and prey.

Traumatic stress in the normal individual results in activation of the sympatho-adrenal system causing a rise in noradrenaline and adrenaline, stimulation of the thyroid system causing increased secretion of thyroid hormones and activation of the hypothalamic-pituitary-adrenocortical (HPA) system resulting in elevated levels of cortisol. Studies in animals and in humans with posttraumatic stress disorder indicate that chronic traumatic stress can result in dissociation of the sympatho-adrenal medullary and the HPA system resulting in sustained elevations of the former system but suppressed or altered ACTH-corticoid responsivity. As reviewed by Henry, self preservative behavior with its emphasis on power and control, is associated with catecholamines, thyroid hormones and left hemispheric functioning while species preservative behavior, with its emphasis on attachment, familiarity, reverence and synchronicity, is associated with cortisol, oxytocin and right hemispheric functioning. Traumatic stress seems to disturb this hemispheric balance which is reflected in the suppression of cortisol and loss of attachment behavior and other species preservative right hemispheric functions.

James Paget Henry really began his productive research career at the outset of the second world war. His studies of acceleration and the anoxia of high altitude were supported by the development of then new techniques of measuring and recording critical physiologic parameters such as vascular pressures, respiratory functions and haemoglobin saturation. His inquisitive mind made productive use of the instruments that had to be made by skilled instrument makers working in university shops. Much of this instrumentation has now found its way into the clinical arena where it is now the main armamentarium of cardiac diagnostic and respiratory function laboratories. His work in the space program preceeded that of the Russians but did not get recognition until Sputnik awakened the world to the possibilities of space flight. His development of the concept of a cardiovascular basis for fluid volume control and the supportive investigative work undertaken constitute a milestone in the annals of experimental physiology. The chimpanzees used in Project Mercury were found to be hypertensive which was related to the method of capture used by the commercial suppliers. This lead Jim to study the effect of early experience on resting blood pressure, an effort that soon developed into provocative studies of the biological basis of the stress response.