Jfx. Jones et al., THE EFFECTS OF ESOPHAGEAL DISTENSION ON DIAPHRAGM AND LARYNGEAL MUSCLE-ACTIVITY IN THE ANESTHETIZED CAT, Experimental physiology, 79(4), 1994, pp. 505-513
The electromyographic (EMG) activities of diaphragm and laryngeal musc
les were recorded during oesophageal distension in anaesthetized cats.
The responses to distension of the thoracic oesophagus differed from
those evoked by distension of the cervical oesophagus. The crural comp
onent of the diaphragm (CD) was inhibited by distension of the thoraci
c oesophagus; distension of the cervical oesophagus did not affect CD
EMG. Thyroarytenoid (TA) muscle EMG increased markedly and consistentl
y in response to distension of the cervical oesophagus. Distension of
the thoracic oesophagus only produced statistically significant increa
ses in TA EMG with high distending volume (10 ml) at the level of the
gastro-oesophageal junction. The main abductor of the vocal cords, the
posterior cricoarytenoid (PCA) was either unchanged or decreased by o
esophageal distension. The electrical activities of left paratendinous
diaphragm, left costal diaphragm, internal intercostal and external i
ntercostal muscles remained unchanged. The entire pattern would appear
to constitute a means to aid passage of a bolus into the stomach, and
simultaneously guard the respiratory tract from reflux or aspiration.