Related Experiment Video
Updated: Sep 26, 2026

Use of the Operant Orofacial Pain Assessment Device (OPAD) to Measure Changes in Nociceptive Behavior
Published on: June 10, 2013
Differences in responses to nociceptive stimulation of the oral and aboral oesophagus
Thomas Hummel1, Sibylle Barz, Tobias Hölscher
1Department of Otorhinolaryngology, University of Dresden Medical School, Fetscherstr. 74, 01307 Dresden, Germany. thummel@rcs.urz.tu-dresden.de
Abstract:
The present study examined the role of vagal innervation of the rat esophagus in nociception. Electromyographic recordings from neck muscles were used as indicators of pseudoaffective reactions in lightly anaesthetized animals; responses were obtained during mechanical (distension) and chemical (HCl) nociceptive stimulation of the upper cervical (4.5 cm from incisors) and midthoracic (7 cm from incisors) esophagus. Compared to midthoracic esophageal stimulation, stimulation of the upper esophagus produced more vigorous responses. Bilateral transections of the cervical vagus and superior laryngeal nerves led to a gradual diminution of responses to upper stimulation, while the same manoeuvre increased responses to lower esophagus stimulation. These results suggest a contribution of vagal afferents to pseudoaffective responses elicited by noxious stimulation of the upper esophagus.
Related Concept Videos
The Physiology of Taste
Local Anesthetics: Differential Sensitivity of Nerve Fibers
Taste Buds and Receptors
Esophageal Achalasia
Analgesia and Pain Management

