Reinnervation of the rat adrenal medulla transplanted in the anterior eye chamber.

Adrenal medulla transplanted to the anterior chamber of the eye was studied by electron microscopy. Transplanted chromaffin cells consisted of noradrenaline cells, adrenaline cells and small granule-containing cells, and they formed long cytoplasmic processes. Some chromaffin cells were directly opposed to the iridial epithelial cells. A few adrenergic and cholinergic ganglion cells were seen in the transplant. Nerve fibres, mostly cholinergic, but a few adrenergic, were seen within satellite cells enclosing chromaffin and ganglion cells. A few synapses were formed on the chromaffin and ganglion cells, though the number of such synapses remained small even 6 months after transplantation. The possible origin of these nerve fibres, and the specificity of reinnervation are discussed.