[Histochemical study on the nitric oxide synthase in the intestinal myenteric plexus of burned rats]

To elucidate the postburn change in the activity and the distribution of nitric oxide synthase (NOS) in rat intestinal myenteric plexus.

The activity and distribution of NOS were quantitatively and locationally studied by histochemical staining with NADPH-diaphorase (NDP), a marker for NOS, and whole mount preparation technique.

NOS was widely distributed in whole intestine wall, especially in myenteric plexus. The majority of NOS positive neurons displayed either round or oval shape. There were some varicosities string of bead-like structure in the nerve fibers and which were accompanied by blood vessels and muscular fibers. There was no significant postburn change in the density of NOS positive neurons in myenteric plexus (P < 0.05). Nevertheless the NOS activity of neurons decreased obviously (P < 0.05 similar 0.01). Meanwhile, it was found after injury that there were indistinction of the structure of NOS positive neuron, more breaking of nerve fibers, leading to the lack of integral web of nerve fibers and obvious decrease of NOS positive varicosities in nerve fibers.

After burn injury, the NOS positive neural structure in myenteric plexus of rat small intestine was damaged with the decrease in NOS activity. Simultaneously, there was impairment of the releasing route of nitric oxide (NO). All these changes might be closely related to intestinal structural damage and dysfunction after burn injury.