Cortisol rapidly increases baroreflex sensitivity of heart rate control, but does not affect cardiac modulation of startle

in Physiology and Behavior (2020), 215(1), 112792

Cortisol, the final product of human HPA axis activation, rapidly modulates the cortical processing of afferent signals originating from the cardiovascular system. While peripheral effects have been ... [more ▼]

Cortisol, the final product of human HPA axis activation, rapidly modulates the cortical processing of afferent signals originating from the cardiovascular system. While peripheral effects have been excluded, it remains unclear whether this effect is mediated by cortical or subcortical (e.g. brainstem) CNS mechanisms. Cardiac modulation of startle (CMS) has been proposed as a method to reflect cardio-afferent signals at subcortical (potentially brainstem-) level. Using a single blind, randomized controlled design, the cortisol group (n = 16 volunteers) received 1 mg cortisol intravenously, while the control group (n = 16) received a placebo substance. The CMS procedure involved the assessment of eye blink responses to acoustic startle stimuli elicited at six different latencies to ECG-recorded R-waves (R + 0, 100, 200, 300, 400 and 500 ms). CMS was assessed at four measurement points: baseline, -16 min, +0 min, and +16 min relative to substance application. Baroreflex sensitivity (BRS) of heart rate (HR) control was measured non-invasively based on spontaneous beat-to-beat HR and systolic blood pressure changes. In the cortisol group, salivary cortisol concentration increased after IV cortisol administration, indicating effective distribution of the substance throughout the body. Furthermore, BRS increased in the cortisol group after cortisol infusion. There was no effect of cortisol on the CMS effect, however. These results suggest that low doses of cortisol do not affect baro-afferent signals, but central or efferent components of the arterial baroreflex circuit presumably via rapid, non-genomic mechanisms. [less ▲]

Pain behavior and spinal cell activation due to carrageenan-induced inflammation in two inbred rat strains with differential hypothalamic-pituitary-adrenal axis reactivity

in Physiology and Behavior (2012), 105(4), 901-908

Psychophysiological responses to idiosyncratic stress in Bulimia Nervosa and Binge Eating Disorder.

in Physiology and Behavior (2011), 104

This study examined psychophysiological stress responses to idiosyncratically relevant stress in bulimia nervosa (BN) and binge eating disorder (BED), in relation to autonomic cardiac control and ... [more ▼]

This study examined psychophysiological stress responses to idiosyncratically relevant stress in bulimia nervosa (BN) and binge eating disorder (BED), in relation to autonomic cardiac control and nutritional status. A total of 81 women with BN, BED and healthy controls (HC) took part in an in sensu exposure to idiosyncratic stress. Psychological and peripheral physiological parameters were measured, and tonic heart rate variability, nutritional status, and types of stress were determined. In response to stress exposure, both eating disordered groups showed a stronger reactivity of sadness, and the BED group showed a stronger reactivity of insecurity than the HC group. Desire to binge was increased in the context of interpersonal stress. Stress exposure led to increased cardiovascular activity and reduced electrodermal activity that did not differ by group. The BN-specific symptomatology moderated the association between autonomic cardiac control and psychophysiological stress responses. The results suggest common and specific psychophysiological processes in symptom maintenance through life stress in BN and BED. [less ▲]

Dietary restriction, cardiac autonomic regulation and stress reactivity in bulimic women

in Physiology and Behavior (2009), 98

Recent !ndings suggest sympathetic inhibition during dietary restriction as opposed to increased sympathetic activity during re-feeding. The present study investigated cardiac autonomic regulation and ... [more ▼]

Recent !ndings suggest sympathetic inhibition during dietary restriction as opposed to increased sympathetic activity during re-feeding. The present study investigated cardiac autonomic regulation and stress reactivity in relation to biochemical markers of dietary restriction status in women diagnosed with bulimia nervosa. We predicted that bulimic individuals (BN) with a biochemical pro!le indicating dietary restriction exhibit reduced cardiac sympathetic and/or increased vagal activity. We also hypothesized, that BN with a biochemical pro!le within a normal range (i.e. currently not dieting or malnourished) would show heart rate variability responses (HRV) and reactivity to mental stress indicating increased sympathetic activation compared with non-eating disordered controls. Seventeen female volunteers diagnosed with bulimia nervosa were categorized according to their serum pro!le (glucose, pre-albumin, IGF-1, TSH, leptin) into currently fasting versus non-fasting and compared with 16 non-eating disordered controls matched for age and BMI. Spectral components of HRV were calculated on heart rate data from resting and mental stress periods (standardized achievement challenge) using autoregressive analysis. Compared to non-fasting BN and controls, fasting BN showed increased vagal and decreased sympathetic modulation during both resting and recovery periods. Cardiac autonomic regulation was not impaired in response to mental challenge. No differences could be found between non-fasting BN and controls. The results con!rm the notion of cardiac sympathetic inhibition and vagal dominance during dietary restriction and suggest the speci!city of starvation related biochemical changes for cardiac autonomic control. The results are discussed in terms of the higher incidence in cardiac complications in these patients. [less ▲]