Figure 2

Concentration-response curves to leptin after phenylephrine precontraction in pulmonary artery compared to thoracic aortic segments. The endothelium-denuded (−) and –intact (+) thoracic aortic and pulmonary artery rings collected from control Wistar (A) and spontaneously hypertensive rats (B) were precontracted with phenylephrine (1 μmol/L) before cumulative addition of leptin (0.001 to 100 nmol/L). Relaxation responses are expressed as the percentages of the maximal tension response obtained with 1 μmol/L phenylephrine. Response curves to leptin after endothelin-1 precontraction in pulmonary artery compared to thoracic aortic segments. The endothelium-denuded (−) and –intact (+) thoracic aortic and pulmonary artery rings from control Wistar rats (C) and spontaneously hypertensive rats (D) were precontracted with endothelin-1 (10 nmol/L) before the addition of leptin (100 nmol/L). Relaxation responses are expressed as the percentages of the maximal tension response obtained with 10 nmol/L endothelin-1. Thoracic aortic and pulmonary artery segments are collected in control Wistar rats (n = 7-13) and in spontaneously hypertensive rats (n = 10-15). Results are expressed as means ± SEM. *** p < 0.001 compared to the corresponding endothelium-intact (+) artery; ♯ 0.01 < p < 0.05, ♯♯ 0.001 < p < 0.01, ♯♯♯ p < 0.001 compared to the thoracic artery in the same strain of rats.