AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 3 686-R689, Copyright © 1991 by American Physiological Society
Role of circulation in maintaining Na+ and K+ concentration in pelvic patch in Rana catesbeiana
R. H. Parsons and R. Schwartz
Department of Biology and Biophysics Center, Rensselaer Polytechnic Institute, Troy, New York 12180-3590.
Skin samples from the pelvic, pectoral, and back areas of frogs were taken
from control (C) animals and from dehydrated animals under three
conditions: dehydrated and not exposed to a bathing medium (D), dehydrated
live and ventral surface exposed to a bathing medium (DL), and dehydrated
with heart stopped and ventral surface exposed to a bathing medium (DHS).
The skin concentration of Na+ and K+ of the pelvic patch in the absence of
circulation was significantly reduced [DHS 286 +/- 22 microM/mg dry wt (n =
6)] compared with control [C 392 +/- 21 microM/mg dry wt (n = 8)]. However,
the pelvic skin concentration was maintained in a frog with an intact
circulation [DL 381 +/- 26 microM/mg dry wt (n = 7)] even in the presence
of a high pelvic water flow [684 +/- 105 cm3.cm-2.s-1.10(-7) (n = 13)]. The
water uptake in the pectoral region [231 +/- 54 cm3.cm-2.s-1.10(-7) (n =
13)] was not high enough to predict a dilution, and none was found. The
concentrations were 354 +/- 21 (n = 8), 359 +/- 22 (n = 7), 353 +/- 26 (n =
7), and 373 +/- 45 microM/mg dry wt (n = 6) for C, D, DL, and DHS,
respectively. Examination of the Na+ and K+ concentrations separately in
the pelvic skin shows that the lower salt content in DHS frogs is mainly
due to a loss of Na+.(ABSTRACT TRUNCATED AT 250 WORDS)
