Local neural regulation of the motility of the striated muscle portion in the mammalian esophagus

The enteric nervous system plays a vital role in gastrointestinal smooth muscle motility. Unlike the tunica muscularis of the stomach, small intestine and large intestine, which is constituted entirely of smooth muscles, the external muscle layers of the mammalian esophagus contain striated muscle fibers. These striated muscle fibers are innervated exclusively by excitatory vagal efferents and terminate on motor endplates. It is believed that peristalsis in the striated esophageal muscle is executed according to a sequence preprogrammed in a medullary swallowing network and modulated via vago-vagal reflexes. By contrast, the presence of a distinct ganglionated myenteric plexus in the striated muscle portion of the mammalian esophagus has long been known. However, the role of the intrinsic nervous system in the peristalsis of the striated muscle portion of the esophagus has remained enigmatic, and has been neglected in terms of peristaltic control. Recently, the regulatory roles of intrinsic neurons in the esophageal striated muscle have been investigated. The esophageal intrinsic neurons may compose a 'local neural reflex pathway' and regulate the motility of the striated muscle via influencing the neurotransmission in the motor endplate.