Location and distribution pattern of nitric oxide synthesizing neuronal cells in the digestive tract and urinary bladder of mice

In order to investigate further the location and distribution pattern of NOS containing neuronal cells in the peripheral autonomic nerve system of digestive tract and urinary bladder, the digestive and bladder organs were stained by NADPH diaphorase- histochemical staining. Some groups of NADPH diaphorase positive neuronal cells were detected along all parts of the digestive tract, including esophagus, stomach, small and large intestine, as well as urinary bladder. In the digestive tract, these cells were existed in a very small number in the submucous layer (submucous plexuses of Meissner) and ubiquitous in the area between the external and internal layer of smooth muscle (myenteric plexuses of Auerbach). In the bladder, those cells existed at the bladder neck, and in the inner layer of the muscle of urinary bladder. Since the number of NADPH diaphorase containing neuronal cells per millimeter square is more numerous in stomach and large intestine, there is a possibility that the amount of nitric oxide in those organs is also higher. These facts suggest an important role for nitric oxide (NO) in those organs. Furthermore, the existence of those cells in the limited area of urinary bladder i.e. in the bladder neck may suggest the role of nitric oxide (NO) in vesico-urethral sphincter muscle function.