TITLE:
The Ventral Ascending Noradrenergic Bundles Are Involved in the Stress Response to Immobilization in Rats
AUTHORS:
Toshihiro Yoshihara, Yasutaka Yawaka
KEYWORDS:
Hypothalamus-Pituitary-Adrenal Axis, Immobilization Stress, 6-Hydroxydopamine, Ventral Ascending Bundles of Noradrenergic Neurons, Rat
JOURNAL NAME:
Journal of Behavioral and Brain Science,
Vol.5 No.3,
March
4,
2015
ABSTRACT: Stressful stimuli induced by immobilization are perceived as acute stress in rats. This acute stress activates corticotropin-releasing hormone (CRH) neurons in the hypothalamic paraventricular nucleus (PVN), resulting in stimulation of the hypothalamic-pituitary-adrenal (HPA) axis. The ventral ascending noradrenergic bundles (V-NAB) from the brainstem innervate the PVN. To investigate the relationship between the response of the HPA axis and the V-NAB, we examined changes in plasma corticosterone, the final output of the HPA axis, and extracellular noradrenaline (NA) in the PVN following immobilization stress in rats that received bilateral 6-hydroxydopamine (6-OHDA) lesions of the V-NAB. 6-OHDA microinjection into the V-NAB reduced the magnitude of the responses of plasma corticosterone and extracellular NA in the PVN following immobilization stress. Our results suggest that V-NAB innervation of the PVN is involved in immobilization stress-induced activation of the HPA axis.