2.5. Data acquisition and signal processing
Recording was made in a quiet room with minimal electrical interference. Prior to installation, calibration of every telemetry device was verified. Throughout the blood pressure (BP) recording an atmospheric-pressure monitor (Model APR-1) automatically subtracted the atmospheric pressure from the BP value given by the transmitter. This provided the actual BP values irrespective of changes in atmospheric pressure. Each individual rat cage was placed on top of a receiver (Model RPC-1) and the signals were recorded through pressure output adaptor (Model R11CPA) for measurement of various cardiovascular parameters. Using the data acquisition software LabChart version 7.3 (ADI instruments, Colorado springs, CO, USA), the experimental data were recorded continuously in real time. From the MAP signal, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were extracted and the HR was calculated between two successive points and expressed in beats per minute (bpm).