A B S T R A C T The purposes of this study were: (a) to compare the effect of gastric vagal stimulation on phrenic nerve activity during respiration and fictive vomiting, (b) to evaluate the modulatory effect of the central pattern generators (CPGs) for respiration and vomiting following peripheral inputs from gastric vagus. Decerebrate, paralyzed, and ventilated cats were used in this study. Vomiting was induced by electric stimulation of the gastric vagus or injection of emetic drugs (e.g. apomorphine). Fictive vomiting was identified by a characteristic series of synchronous bursts of phrenic nerves and abdominal nerves. During respiratory phase, the average duration of the phrenic nerve activity was 0.79 ¡Ó 0.07 second. The average duration of the phrenic cycles was 2.55 ¡Ó 0.13 second. Spectral analysis indicated that the phrenic activation had high frequency oscillation of 85~95 Hz. Gastric vagus stimulation (100 Hz, 300 mA) during respiratory phase lead to a deviation of the phrenic duration of -0.04 seconds. The duration of phrenic cycles was also decreased (reduced 0.25 seconds). The spectral distribution of the phrenic neurogram was also shifted during gastric vagal stimulation (dextral to 100~110 Hz). During vomiting phase, the average duration of the phrenic activity was 0.22 ¡Ó 0.03 seconds which was shorter than that during respiratory phase. The duration of the phrenic cycle during vomiting was 0.54 ¡Ó0.08 second. The major distribution of the power spectrum of the phrenic neurogram during vomiting was 100~120 Hz which is apparently higher than that during the respiratory phase. Gastric vagus stimulation during vomiting showed an averagely increased phrenic cycle (0.74 ¡Ó 0.05 seconds), and a shift of its spectral distribution (dextral to 120~150 Hz). These results suggest that vomiting and respiration were controlled by separate CPGs. Since the output of these two CPGs can be modified by a common peripheral signal such as stimulatary input signal from the gastric vagus, it is postulated that these two CPGs might be highly overlaped. Alternatively, they might be equipped with a single neural network while possessing two separate functions. Normally, this naural network will presume respiratory function, once properly stimulated, such as by injecting apomorphine or by chronic electric stimulation of gastric vagus, functions of this neural network, driving same set of motor fibers (diaphragm and abdominal muscles), will be shifted from respiratory control to vomiting phase control.

Thesis (Ph. D.)--University of Hong Kong. / Typewritten.

published_or_final_version / Zoology / Doctoral / Doctor of Philosophy

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Doctor of Dental Science / This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au

Thesis (Ph. D.)--University of Chicago. / "Reprinted from the Journal of comparartive neurology and psychology, vol. XVI, no. 4, 1906." Includes bibliographical references (p. 28-31). Also available on the Internet.

Inaug.-Diss.--Jena. / Lebenslauf. "Literaturverzeichnis": p. 65-69.

Thesis (Ph. D.)--Indiana University, 2003. / Includes bibliographical references (leaves 114-122). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Inaug.-Diss.--Jena. / Lebenslauf. "Literaturverzeichnis": p. 65-69.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.