Journal of Applied Physiology, Vol 73, Issue 2 713-720, Copyright © 1992 by American Physiological Society
Effect of regular voluntary exercise on resting cardiovascular responses in SHR and WKY pregnant rats
M. T. Jones, K. I. Norton, D. M. Black, R. E. Graham and R. B. Armstrong
Department of Physiology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853.
The purpose of this study was to assess the influence of regular voluntary
exercise in pregnant normotensive Wistar-Kyoto (WKY) and spontaneously
hypertensive (SHR) rats on 1) uteroplacental perfusion and mean arterial
pressure in the resting conscious condition and 2) fetal number, fetal
weight, and number of fetal resorptions. WKYs and SHRs were randomly
assigned to standard cages [CWKY (n = 10); CSHR (n = 6)] or cages with
activity wheels [EWKY (n = 7); ESHR (n = 8)]. EWKYs and ESHRs exercised for
12 wk, and then all rats were bred and experiments were conducted on
gestational day 17. Resting blood flow (microspheres), heart rate (HR), and
mean arterial pressure (Pa) were measured. No significant difference was
found in Pa, HR, uterine blood flow (ESHRs 52 +/- 8 ml.min-1.100 g-1; CSHRs
28 +/- 6 ml.min-1.100 g-1), or maternal placental blood flow (ESHRs, 122
+/- 31 ml.min-1.100 g-1; CSHRs 78 +/- 21 ml.min-1.100 g-1) among the
groups. Exercise altered the relationship between maternal placental and
uterine blood flow and Pa in the SHR; SHRs with lower Pa maintained higher
placental and uterine blood flow after training. Before gestation ESHRs ran
on average more kilometers per week than EWKYs (43 +/- 3 vs. 34 +/- 4), but
during gestation ESHRs averaged fewer kilometers per week than EWKYs (16
+/- 4 vs. 22 +/- 4). Succinate dehydrogenase activity was higher in the
white vastus lateralis (1.02 +/- 0.2 mumol cytochrome c reduced.min-1.g wet
wt-1) and vastus intermedius (3.1 +/- 0.5 mumol cytochrome c
reduced.min-1.g wet wt-1) muscles of ESHRs.(ABSTRACT TRUNCATED AT 250
WORDS)
