Microdialysis delivery of morphine to the hypoglossal nucleus of Wistar rat increases hypoglossal acetylcholine release.

Study Objectives: The medullary hypoglossal nucleus (XII) innervates the genioglossal muscles of the tongue, and opioid-induced alterations in tongue muscle tone contribute to airway obstruction. Previous studies have shown that morphine causes a significant decrease in acetylcholine (ACh) release in some brain regions, but the effects of morphine on ACh release in XII have not been quantified.

Design: A within-subjects design was used to test the hypothesis that morphine alters ACh release in XII of anesthetized Wistar rat.