Background: Methodological improvements in measuring cardiovascular parameters have meant that data can be collected from freely moving animals in their home cage. However, experiments in rabbits still often require them to be restrained in a laboratory setting. The aim of this study was to determine whether measurements collected when the rabbits were constrained in a holding box in the laboratory are representative of values obtained in freely moving conscious rabbits.
Methods: Nine New Zealand white rabbits received 2 radio-telemetry implants to monitor mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA).
Results: MAP measured in the laboratory (71±1mmHg) was similar to that in the home cage (69 ± 1mmHg) but there was lesser MAP variability. RSNA was also similar in both environments. By contrast, laboratory HR was 7% lower than home cage HR (181±4b/min, P<0.001) but HR variability was similar. Baroreflex gain, assessed by spectral analysis, was 19% higher in the laboratory than in the home cage due to lower MAP mid-frequency variability in the laboratory. Home cage circadian patterns of MAP and HR were strongly influenced by feeding and activity. Nevertheless, MAP and RSNA laboratory measurements were the same as average 24 hour values and remained similar over several weeks.
Conclusion: We conclude that while HR is generally lower in the laboratory, MAP and RSNA can be validly represented by laboratory measurements.
Disclosure: No conflict of interest