Bridge amp

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).

The pulsatile arterial pressure (PAP) of anesthetized animals was continuously recorded through the arterial cannula that was connected to a pressure transducer (MLT0380, ADInstruments, Bella Vista, Australia) with an amplifier (Bridge Amp, ML221, ADInstruments, Bella Vista, Australia). Data were digitized at a frequency of 1000 samples per second using an analogue to digital converter (PowerLab 4/25, ML845, ADInstruments, Bella Vista, Australia). MAP was calculated from the integral of PAP's signal (PowerLab 4/25, ML845, ADInstruments, Bella Vista, Australia). HR was calculated as instantaneous frequency from the PAP's signal (PowerLab 4/25, ML845, ADInstruments, Bella Vista, Australia).
The miniatures probes were connected to T206 flowmeter (Transonic Systems, Inc., Ithaca, NY, USA), in order to record the RBF and ABF. The signals obtained were recorded by the acquisition and data analysis MP150 system (PowerLab 4/25, ML845, ADInstruments, Bella Vista, Australia). Data were digitized at a sampling frequency of 200 samples per second. Changes in RBF and ABF were calculated as the percentage relative ratio to baseline (%RBF and %ABF).
The RVC and AVC were obtained by the ratio of RBF/MAP and ABF/MAP, respectively. The variations of RVC and AVC were expressed as percentage change in baseline value (%RVC and %AVC, resp.).

Systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean artery pressure (MAP) were measured in conscious offspring. Pentobarbital sodium (50 mg/kg) was used for anesthesia. Polyethylene catheters (5 cm PE10 combined with 25 cm PE 50, SCI, United States) filled with sterile saline containing heparin (50 U/ml) and penicillin G (2000 U/ml) were inserted into the femoral artery and vein, and its tip was placed in the abdominal aorta. The catheters were tunneled subcutaneously into the back of the neck and sealed with a plastic cap (Abdala et al., 2012 (link); Moreira et al., 2018 (link)). All animals received a subcutaneously injection of penicillin G (30,000 U/100 g) and meloxicam (1 mg/kg). Catheters were flushed the following day with the same solution containing heparin and penicillin. 2 days after surgery, SBP, DBP and MAP were recorded by Power lab 15T, data-acquisition software, using transducer. On the day of the experiments, the catheter was connected to a pressure transducer (MLT1199; AD Instruments) coupled to a preamplifier (Bridge Amp, ML301; AD Instruments) that was connected to a Powerlab computer data acquisition system. Arterial pressure measurements were taken between 09:00 and 12:00 h by an experimenter that was blind to the animal condition. Data was acquired in conscious animals for 60 min during quiet resting periods (n = 12).