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Endogenous hydrogen peroxide in the hypothalamic paraventricular nucleus regulates sympathetic nerve activity responses to L-glutamate.
J Appl Physiol (1985). 2012 Nov; 113(9):1423-31.JA

Abstract

The hypothalamic paraventricular nucleus (PVN) is important for maintenance of sympathetic nerve activity (SNA) and cardiovascular function. PVN-mediated increases of SNA often involve the excitatory amino acid L-glutamate (L-glu), whose actions can be positively and negatively modulated by a variety of factors, including reactive oxygen species. Here, we determined modulatory effects of the highly diffusible reactive oxygen species hydrogen peroxide (H(2)O(2)) on responses to PVN L-glu. Renal SNA (RSNA), arterial blood pressure, and heart rate were recorded in anesthetized rats. L-Glu (0.2 nmol in 100 nl) microinjected unilaterally into PVN increased RSNA (P < 0.05), without affecting mean arterial blood pressure or heart rate. Effects of endogenously generated H(2)O(2) were determined by comparing responses to PVN L-glu before and after PVN injection of the catalase inhibitor 3-amino-1,2,4-triazole (ATZ; 100 nmol/200 nl, n = 5). ATZ alone was without effect on recorded variables, but attenuated the increase of RSNA elicited by PVN L-glu (P < 0.05). PVN injection of exogenous H(2)O(2) (5 nmol in 100 nl, n = 4) and vehicle (artificial cerebrospinal fluid) were without affect, but H(2)O(2), like ATZ, attenuated the increase of RSNA to PVN L-glu (P < 0.05). Tonic effects of endogenous H(2)O(2) were determined by PVN injection of polyethylene glycol-catalase (1.0 IU in 200 nl, n = 5). Whereas polyethylene glycol-catalase alone was without effect, increases of RSNA to subsequent PVN injection of L-glu were increased (P < 0.05). From these data, we conclude that PVN H(2)O(2) tonically, but submaximally, suppresses RSNA responses to L-glu, supporting the idea that a change of H(2)O(2) availability within PVN could influence SNA regulation under physiological and/or disease conditions.

Authors+Show Affiliations

Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22984242

Citation

Cardoso, Leonardo M., et al. "Endogenous Hydrogen Peroxide in the Hypothalamic Paraventricular Nucleus Regulates Sympathetic Nerve Activity Responses to L-glutamate." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 113, no. 9, 2012, pp. 1423-31.
Cardoso LM, Colombari E, Toney GM. Endogenous hydrogen peroxide in the hypothalamic paraventricular nucleus regulates sympathetic nerve activity responses to L-glutamate. J Appl Physiol. 2012;113(9):1423-31.
Cardoso, L. M., Colombari, E., & Toney, G. M. (2012). Endogenous hydrogen peroxide in the hypothalamic paraventricular nucleus regulates sympathetic nerve activity responses to L-glutamate. Journal of Applied Physiology (Bethesda, Md. : 1985), 113(9), 1423-31. https://doi.org/10.1152/japplphysiol.00912.2012
Cardoso LM, Colombari E, Toney GM. Endogenous Hydrogen Peroxide in the Hypothalamic Paraventricular Nucleus Regulates Sympathetic Nerve Activity Responses to L-glutamate. J Appl Physiol. 2012;113(9):1423-31. PubMed PMID: 22984242.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Endogenous hydrogen peroxide in the hypothalamic paraventricular nucleus regulates sympathetic nerve activity responses to L-glutamate. AU - Cardoso,Leonardo M, AU - Colombari,Eduardo, AU - Toney,Glenn M, Y1 - 2012/09/13/ PY - 2012/9/18/entrez PY - 2012/9/18/pubmed PY - 2013/4/13/medline SP - 1423 EP - 31 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J. Appl. Physiol. VL - 113 IS - 9 N2 - The hypothalamic paraventricular nucleus (PVN) is important for maintenance of sympathetic nerve activity (SNA) and cardiovascular function. PVN-mediated increases of SNA often involve the excitatory amino acid L-glutamate (L-glu), whose actions can be positively and negatively modulated by a variety of factors, including reactive oxygen species. Here, we determined modulatory effects of the highly diffusible reactive oxygen species hydrogen peroxide (H(2)O(2)) on responses to PVN L-glu. Renal SNA (RSNA), arterial blood pressure, and heart rate were recorded in anesthetized rats. L-Glu (0.2 nmol in 100 nl) microinjected unilaterally into PVN increased RSNA (P < 0.05), without affecting mean arterial blood pressure or heart rate. Effects of endogenously generated H(2)O(2) were determined by comparing responses to PVN L-glu before and after PVN injection of the catalase inhibitor 3-amino-1,2,4-triazole (ATZ; 100 nmol/200 nl, n = 5). ATZ alone was without effect on recorded variables, but attenuated the increase of RSNA elicited by PVN L-glu (P < 0.05). PVN injection of exogenous H(2)O(2) (5 nmol in 100 nl, n = 4) and vehicle (artificial cerebrospinal fluid) were without affect, but H(2)O(2), like ATZ, attenuated the increase of RSNA to PVN L-glu (P < 0.05). Tonic effects of endogenous H(2)O(2) were determined by PVN injection of polyethylene glycol-catalase (1.0 IU in 200 nl, n = 5). Whereas polyethylene glycol-catalase alone was without effect, increases of RSNA to subsequent PVN injection of L-glu were increased (P < 0.05). From these data, we conclude that PVN H(2)O(2) tonically, but submaximally, suppresses RSNA responses to L-glu, supporting the idea that a change of H(2)O(2) availability within PVN could influence SNA regulation under physiological and/or disease conditions. SN - 1522-1601 UR - https://www.unboundmedicine.com/medline/citation/22984242/Endogenous_hydrogen_peroxide_in_the_hypothalamic_paraventricular_nucleus_regulates_sympathetic_nerve_activity_responses_to_L_glutamate_ L2 - http://www.physiology.org/doi/full/10.1152/japplphysiol.00912.2012?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -