Blood pressure variability and baroreflex sensitivity are not different in spontaneously hypertensive rats and stroke-prone spontaneously hypertensive rats.
OBJECTIVE
To demonstrate and compare hemodynamic phenotypes of blood pressure (BP), blood pressure variability (BPV) and baroreflex sensitivity (BRS) in genetic hypertensive rats.


METHODS
BP was recorded continuously in conscious, freely moving rats using a computerized technique. BPV was expressed as the standard deviation of beat-to-beat BP values during a 1-h period. BRS was determined by measuring the heart period prolongation in response to the elevation in BP produced by an intravenous injection of phenylephrine.


RESULTS
Body weight and heart period were not different between spontaneously hypertensive rats (SHR) and stroke-prone spontaneously hypertensive rats (SHR-SP) at the age of 15 weeks. The BP level was markedly higher in SHR-SP than SHR, whereas there were no significant differences in BPV and BRS. Quantitatively, systolic, diastolic and mean BP were significantly elevated by 36.9%, 42.9% and 39.5%, respectively, in SHR-SP compared with SHR (P < 0.01). However, their variabilities were elevated only by 14.0%, 0.4% and 10.1%, respectively, without statistical significance (P > 0.05).


CONCLUSIONS
BPV and BRS were not changed in parallel with the BP alterations in SHR and SHR-SP.
Zhan
Lin-shu
LS
Department of Pharmacology, Second Military Medical University, Shanghai 200433, China.
Guan
Yun-feng
YF
Su
Ding-feng
DF
Miao
Chao-yu
CY
D000818:Animals; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011919:Rats, Inbred Strains; D013045:Species Specificity