Spectral analysis of arterial blood pressure and pontomedullary
raphe neuronal activity in anesthetized rats.
Leung, Cynthia G., and Peggy Mason.
The Committee on Neurobiology and the Dept. of Pharmacological &
Physiological Sciences, The University of Chicago, MC 0926, 947 East
58th St., Chicago, IL 60637
APStracts 3:0193R, 1996.
Recent evidence suggests that nociceptive modulatory cells in the
nucleus raphe magnus (RM) and adjacent nucleus reticularis
magnocellularis (NRMC) may participate in the modulation of autonomic
processing. Therefore, spectral analyses were used to determine
component frequencies common to both arterial blood pressure and the
activity of RM/NRMC neurons in rats lightly anesthetized with
isoflurane. These analyses detected powerful, extremely low frequency
(period length: 6.4-18.5 min) oscillations in arterial blood pressure
and in the activity of two classes of RM/NRMC neurons, on and off
cells. All on cells discharged during periods of low blood pressure,
whereas all off cells discharged during periods of high blood
pressure. In contrast, the discharge of neutral and regular cells did
not have a consistent relationship to blood pressure. The role of
these cells in nociceptive modulation is also unclear. The results
presented indicate that on and off cells may participate in the
modulation of both autonomic and nociceptive processing.
Received 1 March 1996; accepted in final form 7 May 1996.
APS Manuscript Number R130-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 May 96