AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 1 40-R45, Copyright © 1984 by American Physiological Society
Ethosecretogram: relation of behavior to plasma corticosterone in freely moving rats
I. Shiraishi, K. Honma, S. Honma and T. Hiroshige
An ethosecretogram, which illustrates the phase relation between animal
behavior and plasma hormone levels, was constructed in conscious rats. A
catheter was placed into the right atrium in male rats 2 days before blood
sampling. Plasma corticosterone levels were monitored individually through
the catheter every 5 min over a period of several hours under freely moving
conditions on an Animex, which records spontaneous locomotor activity. The
results showed that the bursts of locomotor activity were temporally
correlated with those of plasma corticosterone level, the peak of the
former preceding the hormone peak by 15 min. Regarding the type of
locomotor activity, feeding and grooming were significantly correlated with
the subsequent hormone elevation, whereas drinking was not. In a separate
series of experiments, effects of feeding and drinking on plasma
corticosterone levels were examined in conscious rats that had been fasted
or water deprived for 24 or 48 h. In both cases, feeding induced a more
pronounced elevation than drinking, although locomotor activity counts per
se increased more sharply in the latter. It is concluded that in the
ethosecretogram specific types of locomotor activity such as feeding and
grooming induce a phase-locked elevation of plasma corticosterone under
freely moving conditions.
