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Leptin deficiency impairs hypercapnic ventilatory responses independently of changes in body weight
Author(s) -
Bassi Mirian,
Carmo Jussara Marcia,
Hamza Sherren,
Hall John Edward
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1026.4
Subject(s) - hypercapnia , leptin , medicine , endocrinology , weaning , tidal volume , obesity , respiratory system
Leptin‐deficient (ob/ob) mice exhibit ventilatory depression during hypercapnia which can be normalized by intracerebroventricular injections of leptin, suggesting a central role of leptin on ventilatory control. However, it is still unclear whether leptin's effect on ventilatory function occurs independently of the weight loss that occurs during leptin treatment. In this study we investigated ventilatory responses to hypercapnia (7% CO2) in 15‐week‐old obese ob/ob mice fed ad‐lib (n=5, 62±1 g) and in non‐obese ob/ob mice (n=5, 26±1 g) that were fed fixed amounts of food since weaning to match the body weight of wild‐type (WT) control mice (n=3, 27±1 g). Pulmonary ventilation (VE), tidal volume (VT) and frequency (FR) were analyzed by the plethysmography method. Our results demonstrate that hypercarpnic ventilatory responses were significantly (P≤0.05) lower in obese ob/ob mice and lean pair‐weighted ob/ob mice compared to WT controls (138±18, 107±25 and 173±40 ml.min‐1, respectively). The reduction in VE appears to be caused by a significantly smaller VT in the ob/ob groups (0.42±0.04 and 0.37±0.03 ml, respectively, for obese and lean ob/ob mice) compared to WT mice (0.54±0.04 ml). Baseline VE and FR during hypercapnia did not differ among the 3 groups. These results suggest that impaired ventilatory responses to hypercapnia in leptin‐deficient mice are independent of changes in body weight.