ATP in the Lateral Hypothalamus/Perifornical area (LH/PFA) Increases CO2 Chemoreflex.

Abstract

The Lateral Hypothalamus/Perifornical area (LH/PFA) is a chemosensitive site and participates in the CO2 ventilatoy response in a vigilance‐state‐dependent manner. Studies provide evidence of a physiological role for ATP in central chemoreception. We tested the hypothesis that ATP acting on LH/PFA contributes to the CO2 ventilatory response. To this end, ventilation (VE) was recorded in unanesthetized rats by whole body plethysmograph, together with EEG and EMG. We dialyzed into the LH/PFA vehicle and then α,β‐methyleneATP (selective P2X receptor agonist; 10 mM) or PPADS (purinergic antagonist; 1 mM), and studied its effects on VE in air and hypercapnia (7% CO2) during the light and dark period of the diurnal cycle. During wakefulness, but not during sleep, α,β‐methyleneATP microdialysis augmented the hypercapnic ventilatory response by 25% during the dark‐active period (2288 ± 80 mL/kg/min) compared with its vehicle (1786 ± 161 mL/kg/min) (P< 0.01), but not during the light. This effect was due to an increased tidal volume. No effect was observed in normocapnia or in a separate group of animals who had the microdialysis probe misplaced (peri‐LH/PFA). PPADS did not change the ventilatory parameters in all groups. These results suggest that ATP exerts, in the LH/PFA, an excitatory modulation in the hypercapnic chemoreflex during wakefulness in the dark‐active period of the diurnal cycle.Support or Funding InformationFAPESPThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.