Prevention of neuropathy in the pyloric sphincter of streptozotocin-diabetic rats by gangliosides.

Abstract

The effect of diabetes on the density of peptide-containing nerves in the pyloric sphincter of streptozotocin-induced diabetic rats and the possible preventive action of the ganglioside mixture AGF1 on the diabetes-induced changes were investigated. Immunohistochemical techniques were used to localize the general neuronal marker protein gene product 9.5 and the neuropeptides, calcitonin gene-related peptide, [met]-enkephalin, neuropeptide Y, substance P, and vasoactive intestinal polypeptide. The density of neurones showing immunoreactivity to the above peptides in nerves supplying the thickened circular muscle layer of the pyloric sphincter was reduced extensively in diabetic rats. In the ganglioside-treated diabetic animals, this reduction was prevented; indeed, calcitonin gene-related peptide- and substance P-like immunoreactivity in the ganglioside-treated diabetic rats exceeded that seen in control animals. In the ganglioside-treated controls, there was no significant difference in the peptide immunoreactivity from that of untreated controls. The results of the present study show that the ganglioside mixture AGF1 is effective in protecting the nerves of the pyloric sphincter from diabetes-induced changes.