Activation of the hypothalamic paraventricular nucleus by acute intermittent hypoxia: Implications for sympathetic long-term facilitation neuroplasticity.

Activation of the hypothalamic paraventricular nucleus by acute intermittent hypoxia: Implications for sympathetic long-term facilitation neuroplasticity. Exp Neurol. 2018 Dec 31;: Authors: Maruyama NO, Mitchell NC, Truong TT, Toney GM Abstract Exposure to acute intermittent hypoxia (AIH) induces a progressive increase of sympathetic nerve activity (SNA) that reflects a form of neuroplasticity known as sympathetic long-term facilitation (sLTF). Our recent findings indicate that activity of neurons in the hypothalamic paraventricular nucleus (PVN) contributes to AIH-induced sLTF, but neither the intra-PVN distribution nor the neurochemical identity of AIH responsive neurons has been determined. Here, awake rats were exposed to 10 cycles of AIH and c-Fos immunohistochemistry was performed to identify transcriptionally activated neurons in rostral, middle and caudal planes of the PVN. Effects of graded intensities of AIH were investigated in separate groups of rats (n = 6/group) in which inspired oxygen (O2) was reduced every 6 min from 21% to nadirs of 10%, 8% or 6%. All intensities of AIH failed to increase c-Fos counts in the caudally located lateral parvocellular region of the PVN. c-Fos counts increased in the dorsal parvocellular and central magnocellular regions, but significance was achieved only with AIH to 6% O2 (P < 0.002). By contrast, graded intensities of AIH induced graded c-Fos activation in the stress-rel...
Source: Experimental Neurology - Category: Neurology Authors: Tags: Exp Neurol Source Type: research