Refinement of telemetry for measuring blood pressure in conscious rats

Abstract

Although considered the 'gold standard' for measuring blood pressure in laboratory animals, telemetry would benefit from refinement. In the present study, we tested the hypothesis that the small telemetric device used for blood pressure recording in mice would work for rats as well and would serve as an alternative for those studies where abdominal cavity space is quite limited (such as in young animals and pregnant females). Here we report that the use of a smaller and lighter telemetric device implanted in the abdominal aorta of rats led to acquisition of stable and high-quality blood pressure and heart rate data, similar to those obtained by using a larger telemetric device developed for rats. The use of smaller transmitters represents an alternative telemetry technique, especially for those cases in which space in the abdominal cavity is particularly limited such as during pregnancy.

Figure 1.

Typical blood pressure tracings of 2 different rats implanted with a telemetric device designed for rats (PAC40) or mice (PAC10). Animals were sampled once every 7 d for 21 d. Tracings are shown in 3 different time scales (30, 2.5, and 0.5 s).

Figure 2.

Group data illustrating the values for (A) mean arterial pressure (MAP, mm Hg) and (B) heart rate (HR, bpm) recorded during the day (white background) or night (gray background) at 7, 14, and 21 d after rats were implanted with a telemetric device designed for either mice (PAC10) or rats (PAC40). Data are expressed as mean ± SEM (n = 6 rats per group); P > 0.05 between groups.

Figure 3.

Radiographs of 2 rats each implanted with a telemetric device designed for either (A and B) mice (PAC10) or (C and D) rats (PAC40).