Experimental autonomic neuropathy in the choroid of streptozotocin-diabetic rats. Electron microscopic observations

The authors used transmission electron microscopy to examine the autonomic nerve plexus of the choroid, in Wistar albino rats with long-term streptozotocin diabetes. Axonal alterations included massive glycogen deposits, honeycomb arrangement of synaptic vesicles, and an accumulation of dense, lamellated, tubulovesicular and multivesicular bodies within the transmitter segments. The alterations affected not only the neuroeffector areas of arterial and venous vessels, but also the close contacts between transmitter segments and melanocytes. Morphometric analysis lead the authors to conclude that the axonal alterations do not simply represent accentuation of age-related phenomena. Instead, they should be considered as manifestations of diabetic autonomic neuropathy.