title: Inhaled hydrogen sulfide: a rapidly reversible inhibitor of cardiac and metabolic function in the mouse.
abstract: BACKGROUND
  Breathing hydrogen sulfide (H2S) has been reported to induce a suspended animation-like state with hypothermia and a concomitant metabolic reduction in rodents. However, the impact of H2S breathing on cardiovascular function remains incompletely understood. In this study, the authors investigated the cardiovascular and metabolic effects of inhaled H2S in a murine model.
  
  
  METHODS
  The impact of breathing H2S on cardiovascular function was examined using telemetry and echocardiography in awake mice. The effects of breathing H2S on carbon dioxide production and oxygen consumption were measured at room temperature and in a warmed environment.
  
  
  RESULTS
  Breathing H2S at 80 parts per million by volume at 27 degrees C ambient temperature for 6 h markedly reduced heart rate, core body temperature, respiratory rate, and physical activity, whereas blood pressure remained unchanged. Echocardiography demonstrated that H2S exposure decreased both heart rate and cardiac output but preserved stroke volume. Breathing H2S for 6 h at 35 degrees C ambient temperature (to prevent hypothermia) decreased heart rate, physical activity, respiratory rate, and cardiac output without altering stroke volume or body temperature. H2S breathing seems to induce bradycardia by depressing sinus node activity. Breathing H2S for 30 min decreased whole body oxygen consumption and carbon dioxide production at either 27 degrees or 35 degrees C ambient temperature. Both parameters returned to baseline levels within 10 min after the cessation of H2S breathing.
  
  
  CONCLUSIONS
  Inhalation of H2S at either 27 degrees or 35 degrees C reversibly depresses cardiovascular function without changing blood pressure in mice. Breathing H2S also induces a rapidly reversible reduction of metabolic rate at either body temperature.
authors: Anesthesia Center for Critical Care Research, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors: Gian Paolo
authors: GP
authors: Volpato
authors: Robert
authors: R
authors: Searles
authors: Binglan
authors: B
authors: Yu
authors: Marielle
authors: M
authors: Scherrer-Crosbie
authors: Kenneth D
authors: KD
authors: Bloch
authors: Fumito
authors: F
authors: Ichinose
authors: Warren M
authors: WM
authors: Zapol
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006862:Hydrogen Sulfide / Q000008:administration & dosage*; D001239:Inhalation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D012119:Respiration / Q000187:drug effects; D013997:Time Factors
chemical_list: D006862:Hydrogen Sulfide