Janes TA, Parra Sanchez AS, Cardani S, Pagliardini S (2025) Progestin infusion into the hypothalamus of CO2-chemoreflex impaired female rats enhances the hypercapnic ventilatory response. Am Physiol Soc 40(S1) doi: 10.1152/physiol.2025.40.S1.1430
Objective: Authors hypothesized that etonogestrel (ETO) infusion into the dorsomedial hypothalamus (DMH) would elicit CO2-chemo reflex recovery similar to that observed in systemically treated female rats.
Summary: The hypothesis was tested by impairing the CO2-chemoreflex in adult female rats by lesioning retrotrapezoid nucleus (RTN) neurons with substance P-conjugated saporin toxin. Preliminary data suggest that ETO induced modest CO2-chemoreflex recovery in rats with moderate-sized RTN lesion by increasing tidal volume and breathing frequency, while hypoxic ventilation was unaffected. In rats with large RTN lesion, no restorative effect was observed. These data suggest a potential ETO-induced compensatory role for DMH neurons following central CO2-chemoreflex impairment but do not rule out contributions from other brainstem nuclei based on previous systemic ETO administration.
Usage: The CO2-chemoreflex was impaired in adult female Sprague-Dawley rats by lesioning RTN neurons with substance P-saporin toxin (SP-SAP).
Related Products: SP-SAP (Cat. #IT-07)