Endogenous hydrogen sulfide in the rostral ventrolateral medulla/Bötzinger complex downregulates ventilatory responses to hypoxia.

Autor: Donatti AF; Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, 14040-904 Ribeirão Preto, SP, Brazil., Soriano RN; Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, 14040-904 Ribeirão Preto, SP, Brazil., Sabino JP; Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, 14040-904 Ribeirão Preto, SP, Brazil., Branco LG; Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, 14040-904 Ribeirão Preto, SP, Brazil. Electronic address: branco@forp.usp.br.
Jazyk: angličtina
Zdroj: Respiratory physiology & neurobiology [Respir Physiol Neurobiol] 2014 Aug 15; Vol. 200, pp. 97-104. Date of Electronic Publication: 2014 Jun 17.
DOI: 10.1016/j.resp.2014.06.007
Abstrakt: Hydrogen sulfide (H2S) is now recognized as a new gaseous transmitter involved in several brain-mediated responses. The rostral ventrolateral medulla (RVLM)/Bötzinger complex is a region in the brainstem that is involved in cardiovascular and respiratory functions. Recently, it has been shown that exogenous H2S in the RVLM modulates autonomic function and thus blood pressure. In the present study, we investigated whether H2S, endogenously produced in the RVLM/Bötzinger complex, plays a role in the control of hypoxia-induced hyperventilation. Ventilation (VE) was measured before and after bilateral microinjection of Na2S (H2S donor, 0.04, 1 and 2 pmol/100 nl) or aminooxyacetate (AOA, 0.2, 1 and 2 pmol/100 nl, a cystathionine β-synthase, CBS, inhibitor) into the RVLM/Bötzinger complex followed by a 60-min period of hypoxia (7% inspired O2) or normoxia exposure. Control rats received microinjection of vehicle. Microinjection of vehicle, AOA or Na2S did not change VE in normoxic conditions. Exposure to hypoxia evoked a typical increase in VE. Microinjection of Na2S (2 pmol) followed by hypoxia exposure attenuated the hyperventilation. Conversely, microinjection of AOA (2 pmol) into the RVLM/Bötzinger complex caused an increase in the hypoxia-induced hyperventilation. Thus, endogenous H2S in the RVLM/Bötzinger complex seems to play no role in the maintenance of basal pulmonary ventilation during normoxia whereas during hypoxia H2S has a downmodulatory function. Homogenates of RVLM/Bötzinger complex of animals previously exposed to hypoxia for 60 min exhibited a decreased rate of H2S production. Our data are consistent with the notion that the gaseous messenger H2S synthesis is downregulated in the RVLM/Bötzinger complex during hypoxia favoring hyperventilation.
(Copyright © 2014 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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