Para aminohippuric acid pah

After housing in a metabolic cage, the rats were i.p. anesthetized with thiopental sodium (60 mg/kg, Cristália, Asuncion, Brazil). The body temperature of each animal was maintained at 37 • C using a servo-controlled heating blanket (LE 13206, LSI Letica Scientific Instruments, Woonsocket, RI, USA), and tracheostomy was performed to reduce airway resistance. A polyethylene catheter (PE-50 tubing) was implanted in the femoral artery for recording BP. A PE-50 catheter was surgically implanted into the right carotid artery for blood sample collection. Urine was collected through a 24G needle (3/4" 0.7 × 19 mm) syringe implanted in the right unclipped kidney. A solution containing 5 mg/min/kg of inulin (Sigma Aldrich, St Louis, MO, USA) and 1.33 mg/min/kg of para-aminohippuric acid (PAH) (Sigma Aldrich, St Louis, MO, USA) was continuously infused via the femoral vein using a pneumatic pump at a rate of 1.2 mL/h (KDS 100, KD Scientific, Holliston, MA, USA). Three samples of urine and blood were collected at 30 min intervals. GFR was determined through inulin clearance, and RPF was determined by PAH clearance. The values obtained from inulin and PAH represent the means of the three collection periods. The GFR and RPF were normalized per gram (g) of kidney tissue.