Catecholamine-containing and acetylcholinesterase-positive nerve fibres in the rabbit conjunctiva

The innervation of the rabbit conjunctiva was investigated histochemically. Nerves containing acetylcholinesterase (AChE) were demonstrated using a copper thiocholine technique. Sympathetic nerve fibres were demonstrated using either the formaldehyde-induced fluorescence (FIF) or glyoxylic acid induced fluorescence (GIF) method. In addition, GIF and AChE-reactions were performed consecutively for the demonstration of fluorescent and AChE-positive nerves in the same specimen. The number of AChE-positive nerve fibres exceeded that of fluorescent fibres. Both fibre types were more numerous in the stroma of the limbal and tarsal conjunctiva than in the fornix. In the epithelium, only a few AChE-positive nerves were observed. These are assumed to be sensory. Most nerves seemed to contain both catecholamine-containing and AChE-positive fibres. However, nerves fibres containing only AChE-activity were also found. The blood vessels of the conjunctiva were innervated by both fluorescent and AChE-positive nerves, the distribution and number of which differed slightly.