Labchart software

In order to record the arterial pressure, the arterial catheter was connected to a pressure transducer which is coupled to an amplifier (Bridge Amp FE221; ADInstruments, Colorado Springs, CO, USA). The pulsatile pressure was recorded continuously with a data acquisition system (PowerLab; ADInstruments, Colorado Springs, CO, USA). The MAP was calculated from the pulsatile signal using the LabChart software (v.7.3.7, ADInstruments, Colorado Springs, CO, USA). Analogical signals of the electrocardiogram (ECG), obtained through electrodes positioned in the forelimbs, were amplified 1000 times and filtered between 100 and 1000 Hz (Bridge Amp; ADInstruments, Colorado Springs, CO, USA). The heart rate (HR) was calculated as instantaneous frequency of the ECG signal (LabChart v.7.3.7, ADInstruments, Colorado Springs, CO, USA). The DIA motor activity signals was amplified 10,000 times (Bridge Amp; ADInstruments, Colorado Springs, CO, USA) and band-pass filtered (100–2000 Hz). The signal were rectified and integrated in 50 ms intervals using LabChart software (v.7.3.7; ADInstruments, Colorado Springs, CO, USA). The DIA motor activity was evaluated by burst amplitude (expressed as percentage difference from baseline) and frequency (considered as respiratory frequency, fR, and expressed in cycles per minute, cpm).

Vascular function was analysed as previously reported^{(34 )} using a Panlab compact organ bath and a PowerLab® 8/30 data acquisition system coupled to appropriate transducers and controlled by LabChart^TM software (ADInstruments). Endothelium-intact aortic rings were contracted with 10⁻⁹–3 × 10⁻⁵ mol/l phenylephrine and relaxed with 10⁻⁹–3 × 10⁻⁵ mol/l acetylcholine (ACh) or 10⁻¹⁰–3 × 10⁻⁶ mol/l sodium nitroprusside.