Leptin into the ventrolateral medulla facilitates chemorespiratory response in leptin-deficient (ob/ob) mice

Aim Leptin, an adipocyte‐derived hormone, is suggested to participate in the central control of breathing. We hypothesized that leptin may facilitate ventilatory responses to chemoreflex activation by acting on respiratory nuclei of the ventrolateral medulla. The baseline ventilation and the ventilatory responses to CO2 were evaluated before and after daily injections of leptin into the retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG) for 3 days in obese leptin‐deficient (ob/ob) mice. Methods Male ob/ob mice (40–45 g, n = 7 per group) received daily microinjections of vehicle or leptin (1 μg per 100 nL) for 3 days into the RTN/pFRG. Respiratory responses to CO2 were measured by whole‐body plethysmography. Results Unilateral microinjection of leptin into the RTN/pFRG in ob/ob mice increased baseline ventilation (VE) from 1447 ± 96 to 2405 ±174 mL min−1 kg−1 by increasing tidal volume (VT) from 6.4 ± 0.4 to 9.1 ± 0.8 mL kg−1 (P