The hypoxic ventilatory response of rats with increased blood oxygen affinity.

Experimental work has established an interspecific relationship between the threshold for the hypoxic ventilatory response and the 'knee' of the Hb-O2 dissociation curve. However, whether this relationship exists intraspecifically remains unclear. To examine the problem further rats were treated with sodium cyanate (NaOCN) to lower P50 and their hypoxic ventilatory response was measured. NaOCN treated rats had a lower PaO2 and higher Hct than control rats. There was no difference between the control and lowered P50 condition in the ventilatory response to hypoxia when % delta VI was plotted against PaO2. The results are consistent with PaO2 sensing chemoreceptors.