A NOVEL ROLE OF THE DESCENDING ANALGESIA SYSTEM IN THE REGULATION OF VAGAL REFLEXES

Abstract

The submedius nucleus of the thalamus (SubM), ventrolateral orbital cortex (VLO) and periaqueductal grey (PAG) constitute a well‐described pain modulatory pathway. Activation leads to depression of nociceptive inputs in the spinal cord via the rostromedial medulla and brainstem descending inhibitory systems. Using transynaptic anterograde viral tracing we noted a neural circuit derived from jugular ganglia vagal afferents innervating the respiratory tree projecting to the SubM, suggestive that vagal afferent pathways may be regulated by SubM‐VLO‐PAG descending modulatory system. In functional studies using urethane anesthetized Sprague Dawley rats, electrical stimulation of the larynx to act..