AJP - Regulatory, Integrative and Comparative Physiology, Vol 267, Issue 4 1008-R1019, Copyright © 1994 by American Physiological Society
Basis for differential coupling between rhythmic discharges of sympathetic efferent nerves
B. Kocsis
National Institute of Neurosurgery, Budapest, Hungary.
The relationships between activities of three sympathetic efferents
[vertebral (VN); cardiac (CN); and renal nerves (RN)] of 45
chloralose-urethan anesthetized cats were investigated using multivariate
spectral analysis. The multiple coherences measuring the extent to which
one nerve signal may be predicted from the other two were very high
(0.77-0.83) at the peak frequency of synchronized rhythmic activity,
indicating that specific components comprised < 20% of the power in the
nerve signals. The pattern of sympathetic activity was characterized by the
partial coherences calculated for different nerve pairs after the
components common for all three nerve signals were removed. In
baroreceptor-intact cats, partialization on the CN signal drastically
reduced the coherences between the VN and RN (0.25), whereas the coherences
between the CN activity and either of the vasoconstrictors remained high
after partialization on the other vasoconstrictor (0.52 and 0.43). In
baroreceptor-denervated cats, partial coherence was high between vertebral
and cardiac nerves (0.52) and low between renal and any other nerve
discharge (0.19-0.20). In individual experiments, five different patterns
of coupling were observed, and their separation was tested by cluster
analysis.
