Physiological Reviews, Vol 76, 193-244, Copyright © 1996 by American Physiological Society
Modulation of cardiovascular control mechanisms and their interaction
P. B. Persson
Physiologisches Institut der Humboldt, Universitat zu Berlin, Medizinische Fakultat (Charite), Germany.
It is generally held that the role of a specific control element can only
be understood within its physiological environment. The reviewed studies
make it clear that there is a potent interplay between locally produced
substances such as adenosine, nitric oxide, prostaglandins, and various
others all interacting with the central level of control. This can occur at
central sites (e.g., nitric oxide in the brain) or in the periphery (e.g.,
neural influence on autoregulation). The interactions are more or less
pronounced during specific physiological challenges. Furthermore, several
of these interactions are altered under pathological circumstances, and in
some cases, the interactions seem to maintain or even augment the severity
of disease. When more than three parameters participate in an interaction,
the resulting regulation may become extremely complex. If these parameters
are nonlinearly coupled with each other, the only way to shed light onto
the nature of control network is by treating it as a black box. With the
use of spectral analysis or nonlinear methods, it is possible to
disentangle the fundamental nature of the system in terms of the complexity
and stability. Therefore, modern developments in cardiovascular physiology
utilizing these techniques, some of which are derived from the "chaos
theory," are reviewed.
