Graded changes in central chemoreceptor input by local temperature changes on the ventral surface of medulla

Abstract

In cats under pentobarbitone anesthesia the effects of focal temperature changes of the chemoceptive areas on the ventral surface of medulla were studied with respect to tidal volume (VT), tidal variation in efferent phrenic activity, (PhrT) and respiratory rate. The close similarities in effect of focal cooling and of hypocapnia on the different respiratory parameters even during constant artificial ventilation indicate that focal temperature changes of the intermediate (I(S)) areas intervene effectively with the normal ventilatory response to CO2 without changing the chemical or physical environment of those neural structures in the brain stem which set respiratory pattern.