Beta-adrenergic and Opioidergic Modulation of Cortisol Secretion in Response to Acute Stress

Abstract

The modulatory action of beta-adrenergic and opioidergic pathways on the cortisol response to acute stressors was investigated using gonadectomized male miniature pigs. Three types of stressors, nose-snare (NS, for 2 min. each on four occasions at 30 min. intervals); high intensity cracker blasts (CB, two blasts at 3 min intervals) and ACTH (1 i.u./kg BW, i.v.) were utilized 80 min after start of blood sampling. For assessment of cortisol blood samples were withdrawn every 20 min for 200 min. In addition, animals received i.v. injections of either isoproterenol (5 microg/ kg) or propranolol (0.5 mg/kg) or naloxone (1 mg/kg) 15 or 30 min before the application of stressor. Stress of repeated NS application as well as ACTH treatment, resulted in immediate secretion of cortisol (p<0.001). Blast of crackers resulted in a transient increase in cortisol (p<0.05). Isoproterenol stimulated the basal cortisol secretion for about 20 min in unstressed pigs (p <0.01) but propranolol had no effects. Isoproterenol also reinforced (p<0.05) the effect of CB, but had no effect on the cortisol response to nose-snare. In contrast, response to NS was reduced (p=0.02) by propranolol. Neither isoproterenol nor propranolol altered the cortisol response to ACTH application. Pretreatment with naloxone significantly increased the cortisol response to NS (p<0.01) and to CB (p<0.01), but had no effects on ACTH-induced cortisol release. In conclusion, the beta-adrenergic involvement is evident in the cortisol response to acute stress of nose-snare. Furthermore, the results indicate that activation of endogenous opioid system during stress mitigates adrenal response.

Heart Rate and Heart‐Rate Variability Responses to Acute and Chronic Stress in a Wild‐Caught Passerine Bird

“…One of the goals of this study was to validate the use of HRV to determine control of HR by the PNS and the SNS in a passerine. The second technique, parasympathetic and sympathetic blockade, is also a common technique used to determine cardiac regulation {e.g., l,ekas et al 1999;Phogat and Parvizi 2007;Wang et al 2007). For our blockade experiments, we used atropine to block the PNS and propranolol to block the SNS.…”

Acute isoproterenol induces anxiety-like behavior in rats and increases plasma content of extracellular vesicles

“…The authors suggested that the observed stimulatory changes in brain function are most likely due to afferent autonomic sensory nerve inputs [13] proposing that isoproterenol administration should provide a highly controllable experimental model to test interoceptive processes [13]. On the other hand, it should also be considered the possibility that the observed central effects could be mediated by the release of peripheral hormones induced by isoproterenol [28,29]. As far as corticosterone is concerned, this hypothesis does not provide a possible explanation to the effect observed in the present study, since isoproterenol at the dose of 5 mg kg −1 did not modify the plasma corticosterone levels.…”