Vagal control of the motor functions of the lower esophageal sphincter and the stomach.

Vagal control of the motor functions of the lower esophageal sphincter and the stomach is briefly reviewed. The vagal influence is in principle the same in the two tissues. There exists one set of vagal fibers which evokes a contractile response. This response is mediated via cholinergic muscarinic receptors. Another set of fibers evokes a relaxation via a non-cholinergic, non-adrenergic mechanism. The neurotransmitter involved in this response is not established. Observations reported in the literature suggest that an interneuron releasing 5-hydroxytryptamine may be involved. At the effector cells vasoactive intestinal polypeptide and/or adenosine triphosphate may be the neurotransmitter(s).