title: Involvement of endogenous central hydrogen sulfide (H2S) in hypoxia-induced hypothermia in spontaneously hypertensive rats.
abstract: Spontaneously hypertensive rats (SHR) display autonomic imbalance and abnormal body temperature (Tb) adjustments. Hydrogen sulfide (H2S) modulates hypoxia-induced hypothermia, but its role in SHR thermoregulation is unknown. We tested the hypothesis that SHR display peculiar thermoregulatory response to hypoxia and that endogenous H2S overproduced in the caudal nucleus of the solitary tract (NTS) of SHR modulates this response. SHR and Wistar rats were microinjected into the fourth ventricle with aminooxyacetate (AOA, H2S-synthezing enzyme inhibitor) or sodium sulfide (Na2S, H2S donor) and exposed to normoxia (21% inspired O2) or hypoxia (10% inspired O2, 30 min). Tb was continuously measured, and H2S production rate was assessed in caudal NTS homogenates. In both groups, AOA, Na2S, or saline (i.e., control; 1 μL) did not affect euthermia. Hypoxia caused similar decreases in Tb in both groups. AOA presented a longer latency to potentiate hypoxic hypothermia in SHR. Caudal NTS H2S production rate was higher in SHR. We suggest that increased bioavailability of H2S in the caudal NTS of SHR enables the adequate modulation of excitability of peripheral chemoreceptor-activated NTS neurons that ultimately induce suppression of brown adipose tissue thermogenesis, thus accounting for the normal hypoxic hypothermia.
authors.affiliation: a Dental School of Ribeirão Preto, 14040-904, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: João Paulo J
authors.initials: JP
authors.lastname: Sabino
authors.affiliation: b Division of Physiology and Biophysics, Department of Basic Life Sciences, Federal University of Juiz de Fora, 35020-220, Governador Valadares, MG, Brazil.
authors.forename: Renato N
authors.initials: RN
authors.lastname: Soriano
authors.affiliation: a Dental School of Ribeirão Preto, 14040-904, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Alberto F
authors.initials: AF
authors.lastname: Donatti
authors.affiliation: a Dental School of Ribeirão Preto, 14040-904, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Rodrigo Restrepo
authors.initials: RR
authors.lastname: Fernandez
authors.affiliation: a Dental School of Ribeirão Preto, 14040-904, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Kwiatkoski
authors.affiliation: c School of Medicine of Ribeirão Preto, 14040-904, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Heloísa D C
authors.initials: HD
authors.lastname: Francescato
authors.affiliation: c School of Medicine of Ribeirão Preto, 14040-904, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Terezila M
authors.initials: TM
authors.lastname: Coimbra
authors.affiliation: a Dental School of Ribeirão Preto, 14040-904, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Luiz G S
authors.initials: LG
authors.lastname: Branco
mesh_terms: D000625:Aminooxyacetic Acid / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001833:Body Temperature Regulation; D006862:Hydrogen Sulfide / Q000378:metabolism*; D007036:Hypothermia, Induced; D000860:Hypoxia / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008845:Microinjections; D051381:Rats; D011918:Rats, Inbred SHR; D017552:Solitary Nucleus / Q000378:metabolism / Q000503:physiopathology; D013440:Sulfides / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D013440:Sulfides; D000625:Aminooxyacetic Acid; C033479:sodium sulfide; D006862:Hydrogen Sulfide
keywords: NTS; SHR; aminooxyacetate; aminooxyacétate; anapyrexia; anapyrexie; body temperature; brainstem; cystathionine beta-synthase; cystathionine béta-synthase; hypoxia; hypoxie; noyau du tractus solitaire; nucleus of the solitary tract; rat spontanément hypertendu; température corporelle; thermoregulation; thermorégulation; tronc cérébral