These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Organization and regulation of paraventricular nucleus glutamate signaling systems: N-methyl-D-aspartate receptors.
    Author: Ziegler DR, Cullinan WE, Herman JP.
    Journal: J Comp Neurol; 2005 Mar 28; 484(1):43-56. PubMed ID: 15717303.
    Abstract:
    Stress activation of the hypothalamo-pituitary-adrenocortical (HPA) axis is mediated in part by glutamatergic neurotransmission. The precise nature of glutamate effects on stress-integrative hypothalamic paraventricular nucleus (PVN) neurons remains to be determined. Therefore, the current study was designed to delineate the organization of glutamate/NMDA receptor systems in the PVN and to assess regulation of PVN glutamate receptor subunit expression by chronic intermittent stress and glucocorticoids. Immunohistochemical studies verified that N-methyl-D-aspartate (NMDA) receptor subunit proteins NR1 and NR2A/2B are expressed in the medial parvocellular PVN, indicating the potential for NMDA receptor regulation of corticotropin-releasing hormone (CRH) release. Dual-label confocal analysis revealed that CRH neurons are apposed by vesicular glutamate transporter 2 (VGLUT2)-containing terminals, consistent with glutamatergic innervation from hypothalamus and/or brainstem. In situ hybridization analysis revealed a significant and selective stress-induced decrease (37%) in NR2B subunit mRNA expression in the CRH-containing region of the PVN. No changes were observed for NR1 or NR2A mRNAs. In contrast, none of the subunits investigated showed altered expression following adrenalectomy with or without low/high-dose corticosterone replacement. Thus, the observed stress regulation is likely mediated by neurogenic mechanisms in the PVN and upstream stress-transducing neurocircuitry. Because a loss of NR2B subunit inclusion in NR receptors would likely confer increased Ca(++) conductance and faster deactivation kinetics, the stress-induced decrease in NR2B mRNA is consistent with enhanced glutamate signaling in the PVN following chronic stress and, perhaps, increased basal HPA activity and more rapid and/or more robust HPA responses to stress.
    [Abstract] [Full Text] [Related] [New Search]