Vagovagal reflex motility patterns of the rat esophagus
1998; American Physiological Society; Volume: 274; Issue: 5 Linguagem: Inglês
10.1152/ajpregu.1998.274.5.r1425
ISSN1522-1490
Autores Tópico(s)Neuroscience and Neuropharmacology Research
ResumoEsophageal reflex motility and its neural correlates were investigated in 94 urethan-anesthetized adult male albino rats. When distended by means of a stationary balloon, the cervical and thoracic esophageal portion responded with a single pressure wave (type I response), whereas the diaphragmatic (intercrural) segment exhibited rhythmic contractions (type II response). Balloon deflation resulted in an off response aboral to the balloon. Bilateral cervical vagotomy or systemicd-tubocurarine abolished all types of reflex responses. Both type I and type II responses were associated with multiunit discharges in the central subnucleus of the solitary tract complex (NTS C ) and the compact formation of the nucleus ambiguus (AMB C ). Type I discharges, consisting of single bursts, and type II discharges, consisting of rhythmic 0.6-Hz bursts, preceded intraesophageal pressure waves in a fixed phase relationship, persisted after contralateral vagotomy, and were eliminated by ipsilateral vagotomy. During neuromuscular paralysis, peak intraburst discharge rates were reduced in both the NTS C and AMB C , with a concomitant decrease in rhythmicity. It is concluded that bolus-evoked peristalsis of the rat esophagus is 1) segmentally organized; 2) effected by a bilateral uncrossed reflex arc consisting of vagal viscerosensory, NTS C premotor, and AMB C motoneurons innervating the striated muscle tunic and 3) strongly facilitated by reafferent feedback.
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