Decreased heat tolerance is associated with hypothalamo-pituitary-adrenocortical axis impairment. - Archive ouverte HAL Access content directly
Journal Articles Neuroscience Year : 2007

Decreased heat tolerance is associated with hypothalamo-pituitary-adrenocortical axis impairment.

(1) , (2) , (2) , (3) , (3) , (1)
1
2
3

Abstract

When rats are exposed to heat, they adapt themselves to the stressor with a wide inter-individual variability. Such differences in heat tolerance may be related to particularities in the hypothalamo-pituitary-adrenocortical (HPA) axis activation. To further this hypothesis, 80 rats instrumented with a telemetric device for abdominal temperature (Tabd) measurement were separated into two groups. Sixty-eight rats were exposed during 90 min at an ambient temperature of 40 degrees C, and 12 rats to an ambient temperature of 22 degrees C. Heat-exposed rats were then divided into three groups using the a posteriori k-means clustering method according to their Tabd level at the end of heat exposure. Heat tolerant rats (Tol, n=30) exhibiting the lowest Tabd showed a slight dehydration, a moderate triglyceride mobilization, but the highest plasma adrenocorticotropic-hormone (ACTH) and corticosterone levels. Conversely, heat exhausted rats (HE, n=14) presented the highest Tabd, a higher degree of dehydration, a greater metabolic imbalance with the lowest plasma triglyceride level and the highest lactate concentration, as well as a lowest plasma corticosterone and ACTH levels. The fact that the proopiomelanocortin (POMC) mRNA content within the pituitary was low despite of a high c-fos mRNA level is also relevant. Current inflammatory processes in HE rats were underlined by lower inhibitory factor kappaBalpha (IkappaBalpha) mRNA and higher tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) mRNA. In conclusion, data show that intolerance to heat exposure is associated to an HPA axis impairment, possibly related to changes occurring in the IkappaBalpha and TNF-alpha mRNA levels.
Embargoed file
Embargoed file
Ne sera jamais visible
Loading...

Dates and versions

inserm-00388024 , version 1 (10-09-2009)

Identifiers

Cite

Virginie Michel, André Peinnequin, Antonia Alonso, Alain Buguet, Raymond Cespuglio, et al.. Decreased heat tolerance is associated with hypothalamo-pituitary-adrenocortical axis impairment.. Neuroscience, 2007, 147 (2), pp.522-31. ⟨10.1016/j.neuroscience.2007.04.035⟩. ⟨inserm-00388024⟩
91 View
0 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More