Mp100a ce

In a subgroup of animals, cardiovascular parameters were measured simultaneously to ventilation. To this end, one day before the experiments, the adult rats were anesthetized with ketamine (80 mg kg⁻¹, ip) and xylazine (7 mg kg⁻¹, ip) and a polyethylene catheter (PE-10 connected to PE-50; Clay Adams, Parsippany, NJ, USA) was inserted into the abdominal aorta through the femoral artery for measurements of pulsatile arterial pressure (PAP). The arterial catheter was then tunneled subcutaneously and exteriorized at the animal dorsum. After that, a temperature recorder was also implanted into the abdominal cavity, as previously described. After surgery, animals were treated with antibiotic (enrofloxacin, 10 mg kg⁻¹, im) and analgesic (flunixin meglumine, 2.5 mg kg⁻¹, sc) and monitored until recovered from anesthesia. On the next day, when the animals were recovered from surgical procedures, the arterial catheter was connected to a pressure transducer (TSD 104A; Biopac systems) and to an amplifier (DA 100C; Biopac systems) for the monitoring of PAP in unanesthetized conditions. PAP was recorded using a data acquisition system (MP100 ACE; Biopac systems) at a sampling rate of 1 kHz. Mean arterial pressure (MAP) and heart rate (HR) were derived from PAP signals (Acqknowledge, v 4.2.3, Biopac Systems).