UPTAKE OF EXOGENOUS FLUORESCENT DI-I BY INTACT JUNCTIONAL EPITHELIUM OF ADULT-RATS ALLOWS RETROGRADE LABELING OF TRIGEMINAL SENSORY NEURONS

Junctional epithelium (JE) is the special attachment tissue between gi ngiva and teeth, and it is well innervated by sensory nerve fibers. We have found that the fluorescent carbocyanine dye, Di-I, can penetrate quickly into intact JE and spread into connective tissue. Di-I contai ning neurons in trigeminal ganglion were found at 3-7 days and were mo stly gone by 3 weeks. We conclude that substances such as Di-I can pen etrate through permeable epithelia such as intact JE where they are pi cked up by sensory nerve fibers and carried to nerve cell bodies.