Effects of central leptin administration on blood pressure in normotensive rats

We tested the hypothesis that intracerebroventricular (i.c.v.) administration of leptin would increase mean arterial pressure (MAP) in ad libitum (AL) fed and food deprived (FD) normotensive rats. Male Sprague–Dawley rats were chronically instrumented with a guide cannula directed at the lateral ventricle and a carotid arterial catheter. Following recovery from surgery, the MAP and heart rate (HR) response to i.c.v. administration of vehicle (5 μl saline over 1 min) or leptin (0.3 μg or 3.0 μg in 5 μl saline) were determined in conscious, unrestrained AL fed ( n=7–10) and 48-h FD ( n=5–10) rats. Food deprivation significantly reduced MAP (AL=116±3; FD=104±3 mmHg; P