cutaneous vasoconstriction in conscious rabbits during alerting
responses detected by hippocampal theta rhythm.
Yu, Ying-Hui, and W. W. Blessing.
Centre for Neuroscience, Departments of Medicine and Physiology,
Flinders University, Bedford Park 5042 SA, Australia
APStracts 3:0297R, 1996.
We determined whether alerting stimuli cause cutaneous
vasoconstriction in conscious rabbits. We compared ear blood flow
with renal, mesenteric and femoral flows, at rest and in response to
non-noxious alerting stimuli which induced theta rhythm (4-9 Hz) in
the simultaneously recorded hippocampal EEG. Theta-inducing stimuli
(eg whistles, fur touches) reduced ear flow by 95+/-6%, commencing 1
-2 s after the EEG change and lasting 45 s. Renal flow did not
significantly change with alerting stimuli; mesenteric and femoral
flows slightly decreased; arterial pressure transiently rose (+10+/-3
mm Hg); heart rate fell (-43 +/- 9 beats/min). At rest, the
coefficient of variation for ear flow (62+/-6%) was greater than for
other flows (P<0.01). Phentolamine (1 mg/kg i.v.) reduced this
coefficient to 29+/-4% (P<0.01). Our study demonstrates that
alerting responses in conscious rabbits are associated with selective
cutaneous vasoconstriction, without increase in flow to skeletal
muscle.
Received 8 September 1995; accepted in final form 11 July 1996.
APS Manuscript Number R553-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 21 August 1996