Temporal nitric oxide dynamics in the paranasal sinuses during humming

Menzel, Lars, Alexander Hess, Wilhelm Bloch, Olaf Michel,
Klaus-Dieter Schuster, Ralph Ga¨bler, and Wolfgang Urban. Tem-
poral nitric oxide dynamics in the paranasal sinuses during humming.
J Appl Physiol 98: 2064 –2071, 2005. First published February 3,
2005; doi:10.1152/japplphysiol.01151.2003.—In this study, the tem-
poral shape of voice-induced nitric oxide (NO) signals in exhaled air
has been investigated in eight healthy individuals by means of laser
magnetic resonance spectroscopy. The results of the experimental part
have been compared with calculated signals obtained by using a
simple one-compartment model of the paranasal sinuses. In the
experimental part, a rapidly increasing NO concentration has been
found when the subjects started humming. After reaching a maximum,
the emission starts to decrease with the shape of an exponential decay
and finally reaches a constant level. The time constant of this decay
(NO washout) is 3.0 1.2 s. The peak height of the NO emission
during humming increases when the time between two humming
processes increases. When no voice-induced NO emission takes place,
the NO concentration in the paranasal sinuses rebuilds again to a
maximum concentration. The typical time constant for the NO recov-
ery is 4.5 3.2 min. A three-compartment model defining exactly the
geometry and anatomy of the paranasal sinuses has been developed
that is based on three main assumptions of the NO dynamics: 1)
constant NO production of the epithelium in the sinuses; 2) the rate of
the chemical reaction of NO with the epithelium of the paranasal
sinuses is proportional to the NO concentration; and 3) the emission
of NO from the sinuses (volume/s) is proportional to the NO concen-
tration. It is shown that the three-compartment model under the
experimental conditions can be reduced to a one-compartment model,
which describes the complete temporal behavior of the NO exchange.