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Updated: Jun 17, 2026
Implantation of Combined Telemetric ECG and Blood Pressure Transmitters to Determine Spontaneous Baroreflex Sensitivity in Conscious Mice
Published on: February 14, 2021
Intra-strain variations of baroreflex sensitivity in young Wistar-Kyoto rats
Vitor E Valenti1, Caio Imaizumi, Luiz Carlos de Abreu
1Department of Medicine, Cardiology Division, UNIFESP, 04039-032, São Paulo, SP, Brazil. valenti@unifesp.br
Purpose:
To compare baroreflex sensitivity among conscious rats of the same strain.
Methods:
Male WKY rats (eight weeks old) were studied. Cannulas were inserted into the abdominal aortic artery through the right femoral artery to measure mean arterial pressure (MAP) and heart rate (HR). Baroreflex gain was calculated as the ratio between variation of HR in function of the MAP variation (?HR/?MAP) tested with a depressor dose of sodium nitroprusside (SNP, 50 microg/kg, iv) and with a pressor dose of phenylephrine (PE, 8 microg/kg, iv). We divided the rats into four groups: 1) Low bradycardic baroreflex (LB), BG between -1 and -2 bpm/mmHg tested with PE; 2) High bradycardic baroreflex (HB), BG < -2 bpm/mmHg tested with PE; 3) Low tachycardic baroreflex (LT), BG between -1 and -2 bpm/mmHg tested with SNP and; 4) High tachycardic baroreflex (HT), BG < -2 bpm/mmHg tested with SNP. Significant differences were considered for p < 0.05.
Results:
Approximately 82% of the rats presented reduced bradycardic reflex while 22 showed attenuated tachycardic reflex. No alterations were noted regarding basal MAP and HR, tachycardic and bradycardic peak and HR range.
Conclusions:
There was alteration in baroreflex sensitivity among rats of the same strain. Care should be taken when interpreting studies employing WKY as a control for the SHR.
