Organization of Central Pathways Mediating the Hering-Breuer Reflex and Carotid Chemoreflex

Abstract

How are respiratory reflex pathways organized centrally? Surprisingly little data are available in the literature that clearly address this basic question. It is generally assumed that afferents from carotid chemoreceptors, vagally-mediated slowly-adapting pulmonary stretch receptors (PSR) and other cardiopulmonary receptors modulate the respiratory rhythm through paucisynaptic central pathways that directly excite or inhibit the respiratory oscillator. The distinct response patterns specific to differing respiratory afferents suggest that the corresponding central pathways are not organized the same. However, precisely how varying central reflex pathways are organized to selectively modulate the respiratory rhythm is not clear.