Autonomic Physiological Responses Research Articles

Does plasma L-arginine level play a role in regulation of blood pressure during exercise and autonomic nervous function?

Little is known of L-arginine's role in autonomic nervous regulation and physiological responses to dynamic exercise. We assessed heart rate and blood pressure during a maximal bicycle ergometer test and heart rate variability at rest in 15 healthy male volunteers, age 22-38 years. Venous blood samples for plasma L-arginine measurements were taken when subjects were sitting at rest before and at the end of exercise. The autonomic nervous function was assessed with time and frequency domain analysis of heart rate variability. Plasma L-arginine level decreased during maximal exercise from 71.4 mumol l-1 to 51.0 mumol l-1 (P < 0.0001) for all subjects studied. The systolic blood pressure during the maximal exercise test was inversely correlated with plasma L-arginine level at rest (r = -0.70, P < 0.01). Normalized low frequency band of power spectral analysis of heart rate variability correlated with L-arginine level at rest (r = 0.66, P < 0.01). In conclusion, plasma L-arginine level decreased in physical exercise, and plasma L-arginine level at rest was positively associated with the sympathetic component of power spectral analysis of heart rate variability at rest, and inversely with systolic blood pressure during physical exercise.

Objective assessment of peritraumatic dissociation: psychophysiological indicators.

The aims of this study were to investigate psychophysiological changes associated with peritraumatic dissociation in female victims of recent rape and to assess the relation between these changes and symptoms of posttraumatic stress disorder (PTSD). Eighty-five rape victims were examined in a laboratory setting within 2 weeks after the rape, and measures of heart rate, skin conductance, and nonspecific movement were collected. Self-report indexes of reactions to the trauma and interviews to assess PTSD symptoms and peritraumatic dissociation were also completed. On the basis of their scores on the Peritraumatic Dissociation Index, the subjects were classified as having low or high levels of dissociation. Items from the index exhibited good internal consistency, and scores were approximately normally distributed. Individuals in the high peritraumatic dissociation group showed a significantly different pattern of physiological responses from those of the low dissociation group. In general, there was a suppression of autonomic physiological responses in the high dissociation group. This group also contained a larger proportion of subjects (94%) identified as meeting PTSD symptom criteria. Also, among the high dissociation subjects there was a discrepancy between self-reports of distress and objective physiological indicators of distress in the laboratory setting. The results provide preliminary support for the idea that there is a dissociative subtype of persons with PTSD symptoms who exhibit diminished physiological reactivity. The results also underscore the importance of assessing dissociative symptoms in trauma survivors.

Chapter 6 Neuroendocrine states and behavioral and physiological stress responses

Publisher Summary This chapter presents a novel, behavioral physiological stress concept that originates from the classical view that stress is a response. This new concept is extended to environment, behavior, and physiology, and it incorporates the novel neuroendocrine views including the neuropeptide concept. Stress is viewed as a general biological and usually functional response to environmental and bodily demands. A stress depends on interactions among environment, individual characteristics and the properties of stressors, stress, and the physiological systems, and also among the nervous system, peripheral organ systems, and the neuroendocrine system. To adapt to the altering social and physical environmental demands, man and other animals require a chain of behavioral, neuroendocrine, and autonomic physiological and metabolic responses to maintain bodily and mental homeostasis. The neuroendocrine state of the brain is given a central position in determining the state of health or disease of mind and body.

The role of reinforcement and motivation in biofeedback performance

Results of several studies were discussed in order to illustrate the relative importance of reinforcement and incentives to performance in biofeedback experiments. Data were taken from studies employing essential hypertensives, brain damaged patients, and normals as subjects. Both somatic and autonomic physiological responses were monitored. Results indicate that motivational variables play a predominant role in controlling performance on relatively easy biofeedback tasks, while in difficult biofeedback learning tasks, reinforcement plays a predominant role in controlling performance.