AJP - Regulatory, Integrative and Comparative Physiology, Vol 267, Issue 2 387-R399, Copyright © 1994 by American Physiological Society
Differential relationships among the 10-Hz rhythmic discharges of sympathetic nerves with different targets
G. L. Gebber, S. Zhong, S. M. Barman, Y. Paitel and H. S. Orer
Department of Pharmacology/Toxicology, Michigan State University, East Lansing 48824-1317.
Partial coherence analysis was used to remove the influences of the central
circuits controlling a sympathetic nerve (as reflected by its discharges)
on the coherence of the 10-Hz discharges of other sympathetic nerves in
unanesthetized decerebrate or urethan-anesthetized cats. In many cases,
partialization reduced but did not eliminate the sharp peak near 10 Hz in
the coherence functions relating the discharges of sympathetic nerve pairs.
This observation implies that the central sources of the 10-Hz rhythmic
discharges of any nerve are not identical to those responsible for the
rhythm recorded from any other nerve. Partial coherence analysis also
revealed differential relationships among the 10-Hz rhythmic discharges of
sympathetic nerves with different targets. Importantly, the pattern of
differential relationships observed in one experiment could be the reverse
of that in the next. Although the basis for the differential relationships
is not yet clear, nonuniform coupling of multiple brain stem 10-Hz
oscillators and/or nonuniform cross talk between spinal circuits
controlling different sympathetic nerves may be involved.
