AJP - Regulatory, Integrative and Comparative Physiology, Vol 242, Issue 5 482-R490, Copyright © 1982 by American Physiological Society
Renal function, heart rate, and blood pressure during exercise and avoidance in dogs
A. Grignolo, J. P. Koepke and P. A. Obrist
The effects of two behavioral tasks, treadmill exercise and shock
avoidance, on renal and cardiovascular function were examined in dogs
during intravenous infusion of isotonic saline. Urine was collected with a
bladder catheter. Control experiments established steady base lines of
urine flow (V), sodium excretion (UNaV), glomerular filtration rate (GFR),
free water clearance (CH2O), heart rate (HR), and arterial pressure (Pa).
Exercise led to increased V, UNaV, GFR, HR, and Pa with no change in CH2O.
Avoidance caused decreases in V and UNaV, increases in HR and Pa but no
change in either GFR or CH2O. The hematocrit increased significantly during
both tasks. Exercise and avoidance led to opposite urinary changes even
when HR accelerations were identical. The natriuretic effect of exercise
was the consequence of an increased filtered load, while the
antinatriuretic effect of shock avoidance was apparently due to an
increased rate of tubular reabsorption of filtrate. The results show that
exercise and shock avoidance, while eliciting similar cardiovascular
changes, lead to opposite adjustments in urine and sodium output.
