Biology Reference
In-Depth Information
Chapter 18
Using Plethysmography to Determine Erythropoietin's
Impact on Neural Control of Ventilation
Tommy Seaborn , Max Gassmann , and Jorge Soliz
Abstract
The evaluation of respiratory parameters often requires the use of anesthetics (that depress the neural
network controlling respiration), and/or ways to restrain the animal's mobility (that produces a stress-
dependent increase of respiration). Consequently, the establishment of plethysmography represented an
invaluable technique in respiratory physiology. Plethysmography, indeed, allows the assessment of ventila-
tory parameters on living, unanesthetized, and unrestrained animals. The conception of the barometric
plethysmography relies on the fact that an animal placed inside a hermetically closed chamber generates
through its breathing a fluctuation of pressure in the chamber than can be recorded. Thus, the respiratory
frequency and the tidal volume can be directly measured, while the animal's ventilation is calculated indi-
rectly by the multiplication of these two parameters. In our hands, plethysmography was a key tool to
investigate the impact of erythropoietin (Epo) on the neural control of hypoxic ventilation in mice.
Key words
Lung capacity, Mouse, Respiration, Respiratory frequency, Tidal volume, Ventilation,
Hypoxia
1
Introduction
Plethysmography is a reliable method to measure ventilation in
several animal species, including mouse (
1, 2
), rat (
3
), shrew (
4
),
guinea pig (
5
), cat (
6
), dog (
7
), pig (
8
), sheep (
9
), horse (
10
),
and primates (
11
). In humans, this technique is also commonly
used as a clinical tool to determine the functional residual capac-
ity as well as the lung's total capacity. Concerning small mammals
in which the evaluation of gases in blood is challenging, plethys-
mography allows to obtain a subsampling of air that in turn allows
the evaluation of metabolic parameters (O
2
consumption and
CO
2
production). The metabolic assessment is essential in order
to determine whether changes in ventilation and/or the ventila-
tory pattern are due to regulations on the neuronal network con-
trol system, or reflect only the alteration of metabolic parameters.
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