Connections between Adrenergic Nerves and other Tissue Components in the Eye

Abstract

The connections between adrenergic nerve fibres and other ocular structures were studied in normal embryonic material (man, dogs, cats, guinea‐pigs, and rats) as well as with a special vessel injection technique (adult rats, guinea‐pigs, and rabbits). It was established that adrenergic fibres are a normal constituent of the cornea. The adrenergic nerves were more numerous in the embryo than in the adult, and also occurred within the embryonic corneal epithelium. These intraepithelial fibres disappear shortly after birth. Adrenergic fibres running in the connective tissue without connection to vessels were further found in the iris, the limbus region, the chamber angle (of the guinea‐pig predominantly) and in the chorioid. It cannot be excluded that these fibres innervate some connective tissue component. In the sphincter pupillae, only a few adrenergic fibres were connected to the vessels, such as was the case also in the ciliary muscle of the guinea‐pig. Under the ciliary epithelium of the ciliary body and the ciliary processes there was a thick and dense plexus of adrenergic fibres. Only a restricted number of them was associated with the vessels. The “capillaries” of the ciliary processes were remarkable in that they seemed to possess adrenergic fibres. No adrenergic innervation to the melanophores was apparent.