Journal of Dental Research, Vol 74, 1235-1239, Copyright © 1995 by International & American Associations for Dental Research Online Journals
Effect of lung inflation on levator veli palatini muscle activity
H. Koizumi, M. Kogo and T. Matsuya
First Department of Oral and Maxillofacial Surgery, Osaka University Faculty of Dentistry, Japan.
Palatal movements play a critical role in regulating oropharyngeal airflow
during breathing. We hypothesized that these movements are coordinated with
breathing movements via afferent signals from the lung. However, the
control of palatal movements in relation to the lung remains unclear. This
study was designed to define, by electromyographic techniques, the
relationship between palatal movement and lung action during respiration.
We performed tracheotomies on 12 mongrel dogs anesthetized with sodium
pentobarbital and found that lung inflation augmented the activity of the
levator veli palatini muscle (LVP). Two kinds of discharges were recognized
during the expiratory pause following lung inflation. One was a continuous,
low-amplitude discharge induced during apnea following lung inflation. The
other was a transient, high-amplitude discharge which appeared immediately
after lung inflation. Both of these response activities were eliminated by
bilateral vagotomy. We thus concluded that palatal movements, which can
regulate expiratory airflow resistance and cause switching from nasal to
oral airflow, are under the control of vagal afferent signals from the
lung.
