The role of the area postrema in belching

Abstract

Introduction: The primary reflex involved with belching is associated with the activation of neurons in the area postrema (AP), therefore, we investigated the role of the AP in the activation of belching. Methods: The effects of mechanical lesions of the dorsal brainstem on activation of belching, esophago-UES contractile reflex (EUCR), and the pharyngeal swallow (PS) were determined in 13 decerebrate cats. Discussion: Bilateral lesions of the dorsal brain stem which included the rostral AP significantly (P< 0.05, N = 7) blocked belching, but not the other reflexes. Bilateral lesions of the rostral AP only blocked belching (N=2). When belching was blocked, the same belch stimulus activated EUCR (in 6 out of 7 animals). Unilateral lesions of the AP (N = 3) did not block belching. Conclusions: The rostral AP is essential for activation of belching. We hypothesize that the AP serves an inhibitory function to prevent reflexes that promote orthograde transport, e.g. PS, and reflexes that prevent supra-esophageal reflux, e.g. EUCR, thereby, facilitating retrograde transport. Keywords: Belching; brain stem; area postrema.