The adrenergic and cholinergic innervation of the thyroid chicken gland.

The morphology and distribution of the cholinergic and adrenergic nerve fibres were described in the thyroid gland of the domestic hen. The adrenergic structures were visualised with glyoxylic acid and with immunohistochemical staining for tyrosine hydroxylase (TH), the marker for adrenergic nerve structures. Cholinergic structures were visualised using the Karnovsky and Roots method. It was found that the thyroid gland is supplied with numerous adrenergic and cholinergic nerve fibres, which occur as small or large bundles or single nerve fibres. These were located around blood vessels, under the fibrous capsule and in the vicinity of secretory vesicles.