Continuous recordings of regional circulation in the brain of
freely behaving rats during sleep/wake state transitions.
Gerashchenko, Dmitry, and Hitoshi Matsumura.
Department of Molecular Behavioral Biology, Osaka Bioscience
Institute, Suita, Osaka 565, Japan
APStracts 2:0329R, 1995.
Continuous measurement of regional blood flow (RBF) in the brain of a
freely behaving rat was attained by a combination of laser-Doppler
(LD) flowmetry and our originally devised apparatus, which had been
developed for the automatic releasing of the twisting of lines
connected between experimental apparatus and the freely behaving
animal. RBF changes were studied in a ventral region of the rostral
basal forebrain along with sleep-wake states. When compared with the
RBF level during slow-wave sleep (SWS), levels of RBF during
paradoxical sleep (PS) and wakefulness were higher by 24% (P =
0.0001) and 9% (P < 0.05), respectively. The LD signals
suggested that the RBF elevation during PS was produced by dilation
of both the large brain arteries and small vessels, whereas the
elevation during wakefulness was caused by dilation of small vessels
that was counteracted by contraction of large arteries. It was
noticed that the regional circulation tended to begin changing before
the onset of SWS. A circadian rhythm was also demonstrated for the
RBF, which largely decreased around the onset of the light period and
returned to the high level before the beginning of the dark period.
Thus, continuous and real-time recordings of regional circulation
were performed with satisfactory precision in freely behaving rats.
Received 6 June 1995; accepted in final form 7 November 1995.
APS Manuscript Number R332-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95