The dorsal motor nucleus of the vagus and regulation of pancreatic secretory function

Abstract

New Findings: • What is the Topic of this review? This review describes new evidence for the control of pancreatic exocrine and endocrine secretion by the dorsal motor nucleus of the vagus. It describes the effects of several gastrointestinal peptides on pancreatic secretion and considers their sites of action in the vago-vagal reflex pathway. • What advances does it highlight? This review draws together recent electrophysiological, anatomical and pharmacological studies to provide a state-of-art view of the parasympathetic control of the exocrine and endocrine pancreas. Recent investigation of the factors and pathways that are involved in regulation of pancreatic secretory function (PSF) has led to development of a pancreatic vagovagal reflex model. This model consists of three elements, including pancreatic vagal afferents, the dorsal motor nucleus of the vagus (DMV) and pancreatic vagal efferents. The DMV has been recognized as a major component of this model and so this review focuses on the role of this nucleus in regulation of PSF. Classically, the control of the PSF has been viewed as being dependent on gastrointestinal hormones and vagovagal reflex pathways. However, recent studies have suggested that these two mechanisms act synergistically to mediate pancreatic secretion. The DMV is the major source of vagal motor output to the pancreas, and this output is modulated by various neurotransmitters and synaptic inputs from other central autonomic regulatory circuits, including the nucleus of the solitary tract. Endogenously occurring excitatory (glutamate) and inhibitory amino acids (GABA) have a marked influence on DMV vagal output to the pancreas. In addition, a variety of neurotransmitters and receptors for gastrointestinal peptides and hormones have been localized in the DMV, emphasizing the direct and indirect involvement of this nucleus in control of PSF. © 2012 The Authors. Experimental Physiology © 2012 The Physiological Society.