Endogenous preoptic hydrogen sulphide attenuates hypoxia-induced hyperventilation.

Abstract

AIM:

We hypothesized that hydrogen sulphide (H2 S), acting specifically in the anteroventral preoptic region (AVPO - an important integrating site of thermal and cardiorespiratory responses to hypoxia in which H2 S synthesis has been shown to be increased under hypoxic conditions), modulates the hypoxic ventilatory response.

METHODS:

To test this hypothesis, we measured pulmonary ventilation (V˙E) and deep body temperature of rats before and after intracerebroventricular (icv) or intra-AVPO microinjection of aminooxyacetate (AOA; CBS inhibitor) or Na2 S (H2 S donor) followed by 60 min of hypoxia exposure (7% O2 ). Furthermore, we assessed the AVPO levels of H2 S of rats exposed to hypoxia. Control rats were kept under normoxia.

RESULTS:

Microinjection of vehicle, AOA or Na2 S did not change V˙E under normoxic conditions. Hypoxia caused an increase in ventilation, which was potentiated by microinjection of AOA because of a further augmented tidal volume. Conversely, treatment with Na2 S significantly attenuated this response. The in vivo H2 S data indicated that during hypoxia the lower the deep body temperature the smaller the degree of hyperventilation. Under hypoxia, H2 S production was found to be increased in the AVPO, indicating that its production is responsive to hypoxia. The CBS inhibitor attenuated the hypoxia-induced increase in the H2 S synthesis, suggesting an endogenous synthesis of the gas.

CONCLUSION:

These data provide solid evidence that AVPO H2 S production is stimulated by hypoxia, and this gaseous messenger exerts an inhibitory modulation of the hypoxic ventilatory response. It is probable that the H2 S modulation of hypoxia-induced hyperventilation is at least in part in proportion to metabolism.

• Authors: M Kwiatkoski, R N Soriano, G S F da Silva, H D Francescato, T M Coimbra, M L Glass, E C Carnio, L G S Branco
• Journal: Acta physiologica (Oxford, England) (Acta Physiol (Oxf)) Vol. 210 Issue 4 Pg. 913-27 (Apr 2014) ISSN: 1748-1716 [Electronic] England
• PMID: 24119224 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2013 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Chemical References

• Aminooxyacetic Acid
• Hydrogen Sulfide

Topics

• Aminooxyacetic Acid (administration & dosage, pharmacology)
• Animals
• Hydrogen Sulfide (administration & dosage, pharmacology)
• Hyperventilation (metabolism)
• Hypoxia (complications)
• Male
• Preoptic Area
• Rats
• Rats, Wistar