The nucleus raphe magnus modulates hypoxia-induced hyperventilation but not anapyrexia in rats.

Abstract

The nucleus raphe magnus (NRM) is one of the brainstem cell groups involved in physiological responses to hypoxia. Thus, we tested the hypothesis that the NRM modulates hypoxia-induced hyperventilation and anapyrexia. To this end, we assessed the participation of NRM in the respiratory and thermoregulatory responses to hypoxia using ibotenic acid lesions produced in the NRM of rats. Our results demonstrated that, under resting breathing, NRM plays no role in ventilation or body temperature. Hypoxia caused hyperventilation and anapyrexia in all groups. NMR lesions elicited an increased ventilatory response to hypoxia due to a higher tidal volume (V(T)) but did not affect hypoxia-induced anapyrexia. Therefore, we conclude that NRM exerts an inhibitory modulation of breathing during hypoxia, acting on V(T), but plays no role in the hypoxia-induced anapyrexia.

• Authors: Luciane H Gargaglioni, Norberto C Coimbra, Luiz G S Branco
• Journal: Neuroscience letters (Neurosci Lett) Vol. 347 Issue 2 Pg. 121-5 (Aug 21 2003) ISSN: 0304-3940 [Print] Ireland
• PMID: 12873742 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Animals
• Body Temperature Regulation
• Fever (etiology, physiopathology)
• Hyperventilation (etiology, physiopathology)
• Hypoxia (complications)
• Male
• Raphe Nuclei (physiopathology)
• Rats
• Rats, Wistar