Acta physiologica Scandinavica. Supplementum最新文献

In JP Henry's work, fighting for and losing control were important concepts in the interpretation of energy mobilization in psychosocial conditions. Attachment and support were important protective and salutogenic factors. These concepts have been applied in a series of epidemiological and psychophysiological real life studies. Job conditions which force the worker to mobilize energy and concomitantly inhibit anabolism could be identified at least partly by means of the demand-control-support model originally proposed by Karasek. The most adverse conditions at work arise when psychological demands are high and at the same time the decision latitude is low. This combination is associated with changes in the regulation of endocrine parameters as well as with increased morbidity--heart disease, functional gastrointestinal symptoms and musculoskeletal disorders. Examples of studies of physiological correlates of psychosocial processes leading to fight for control are also described from outside work activities.

A state of 'vital exhaustion', characterized by unusual tiredness, increased irritability and feelings of demoralization has been found to preceed the onset of myocardial infarction and to increase the risk of a new coronary event after angioplasty. Probably this state reflects a decreased activity of the hypothalamic-pituitary-adrenal axis as part of an homeostatic reaction to prolonged stress and inflammation.

Jim Henry is best known for his seminal research on psychosocial stress and cardiovascular disease, and studies of the neuroendocrine correlates of animal behaviors during stress. However, he had a wide range of interests, made important contributions in many other areas, and served as a remarkable catalyst in advancing the work of other scientists. These numerous and less appreciated accomplishments could not possibly be covered in an article of this length. Hopefully, some personal observations, and a brief sketch of his extension of Carl Jung's research and his involvement in the U.S. space program, may help to illustrate the superb character and qualities of this modest and multifaceted individual, as well as a few of his lesser known, but equally meaningful achievements.

Ever increasing applications of sophisticated technologies in western civilization have placed great and growing demands for the rapid and accurate processing of multi-modal sensory information. These information streams may exceed an individual's performance capabilities. Failure to respond appropriately may have serious consequences, not only for the individual but also for others, as in command situations in the aerospace environment. There are, for example, consistent patterns common to EEG records in a population of astronaut candidates, when exposed to increasing visual information overload, simulating hazardous flight conditions. The records are dominated at the point of "information overload" by sharply and progressively increased theta wave (4-7 Hz) activity in temporal regions, major increments in frontal beta (> 14 Hz) activity, and markedly reduced occipital alpha (8-12 Hz) levels. These responses to a simulated stress raise questions about the brain's ability to distinguish natural reality from the mediated reality in modern life. It has been hypothesized that an individual's reactions with computers, television and new media are fundamentally social and natural, just as in interactions in real life. Also immune responses may here offer valuable benchmarks concerning reactions to mentally stressful stimuli. Another type of environmental influences in modern society is that of electromagnetic fields. Even fairly weak (athermal) electromagnetic fields have proven to be useful tools to study regulatory mechanisms in cells from brain and other tissues. There is growing evidence that nitric oxide may influence normal EEG patterns and that it may also participate in the pathophysiology of oxidative stress disturbances, including influences in e.g. Parkinson's and Alzheimer's diseases, then behaving as a free radical with reactive-oxygen-species or reactive-nitrogen-species. As a free radical, nitric oxide is sensitive to a variety of imposed magnetic fields, with theoretical and experimental evidence that its actions in regulating the rate and amount of product of cerebral biochemical reactions may also be modulated by imposed magnetic fields.

The seminal work of Henry and Gauer lead us to a) show that in healthy humans cardiopulmonary receptors (CPR) regulate renin release, b) that low renin hypertension is associated with an expanded cardiopulmonary volume. This suggested that the low renin state in hypertension may be due to excessive inhibition of renin by the CPR. In the course of these experiments we uncovered an undescribed pressor reflex which was used to investigate the effect of intermittent pressor episodes on cardiac structure in dogs. Finally, in recent years, we used unloading of CPR to show that reflex vasoconstriction causes acute insulin resistance in the human forearm.

Jim Henry wrote extensively about emotional expressive styles, such as alexithymia which is characterized by reduced awareness of one's own or others' feelings and emotions, and their relation to cerebral hemispheric asymmetries. The repressive coping style is a stable individual characteristic, which is marked by reduced and minimized reports of stress coupled with higher levels of autonomic, somatic, and behavioural responsivity. The apparent dissociation between subjective and physiological response may be associated with a functional disconnection between the two cerebral hemispheres and with greater cerebral lateralization. To test this hypothesis, we reexamined data from a study in which emotional and neutral slides were presented unilaterally to the left and right hemisphere. Exposure duration was 200 ms. Subjects were divided into four different coping styles based on their defensiveness and anxiety scores. Repressive copers were the only group to show a significant cardiac response (heart rate deceleration) to emotional material when it was presented to the right but not to the left hemisphere. These findings and the fact that repressive copers have a high need for social approval support Henry's views about the role of the right hemisphere in affiliation and human bonding.

The sense of taste plays a crucial role in a fish's ability to locate and select appropriate food. Functionally, the taste system is divisible into two subsystems, with external taste, utilized to locate food in the environment, being mediated by the facial nerve while intraoral taste, crucial for triggering swallowing, is mediated by the vagus nerve. Each of these nerves connects to its own portion of the medullary viscerosensory column. In most teleosts, the viscerosensory column forms a continuous, relatively undifferentiated column of neuropil in the dorsomedial medulla. The taste bud-bearing surfaces of the fish are mapped onto this column with external taste buds being represented anteriorly and pharyngeal taste buds caudally. Taste information reaching the vagal taste area, the "vagal lobe", is relayed directly to motoneurons that control the oropharyngeal musculature. In goldfish, unlike most teleosts, the vagal lobe is laminated, highly differentiated structure containing both sensory and motor layers. This derived neural structure is related to the specialized palatal food sorting apparatus utilized by the fish to separate food from substrate material. Despite the complex morphology of the vagal lobe in goldfish, the underlying circuitry is essentially identical to that of other fishes, i.e. after an obligatory synapse in the sensory layers, the gustatory input is relayed to the oropharyngeal motoneurons comprising the motor layer. Thus evolution of the derived, laminated brain structure did not entail generation of new connectivity but merely involved rearrangement of previously existing neuronal populations.

Review of literature suggests that emotional and social stress is a contributory factor to the development of hypertension. If so, relaxation and stress management therapy may reduce high blood pressure (BP) and its complications. In a series of studies I and my colleagues have shown that this may be so. These studies have been published elsewhere and are briefly summarized here.

The old concept that stress depresses immunity must be qualified. There is now evidence that in the same way that different perceptions of stress have different physiological consequences, different ways of coping with stress result in different consequences on immunity, the nature and outcome of which depend on the type of immune response. The mechanisms that are involved in these effects involve neuroendocrine and autonomic pathways. These pathways are actually part of a network of bidirectional interactions between the central nervous system and the immune system, which plays an important role in the physiological regulation of immunity.