The role of the nerve in maintenance of frog taste buds

After denervation, frog taste buds progressively decreased in size over a period of months. In early stages, the predominant event was cell shrinkage; in later stages, it was cell loss. The rate of cell loss in the denervated taste bud was approximately the same as the rate of cell birth in the innervated taste bud, but after denervation, DNA synthesis and mitosis were markedly impaired. The effects of denervation could not be attributed to over-all changes in blood flow. Thus, the gustatory nerve is concerned with day-to-day maintenance of adult cells, and control of DNA synthesis and mitosis of germinative cells. In a few cases, the effects of denervation were reversed in part by either cutaneous or lingual nerve reinnervation: i.e., the trophic role is not an exclusive property of gustatory nerves.