Adrenergic Innervation of the Parasympathetic Ciliary Ganglion in the Chick
Dario Cantino 1 and
Enrico Mugnaini 2
1 Istituto di Anatomia Umana Normale, Università di Torino, Torino, Italy
2 Laboratory of Neuromorphology, Department of Biobehavioral Sciences, University of Connecticut, Storrs 06268
The chick ciliary ganglion receives a nonvascular symathetic innervation in addition to the well-known cholinergic one; fluorescent, varicose adrenergic fibers form pericelluar baskets. Adrenergic fibes were identified electron microscopically in ganglia fixed with potassium permanganate. The fibers degenerate after injection of 6-hydroxydopamine. No true synaptic relationships involving adrenergic varicosities and ganglion cells or cholinergic terminals were demonstrable. The distribution of the adrenergic fibers suggests a kind of "distance à synapse" with the choroidal cells or with the preganglionic fibers (or both). The adrenergic innervation might provide a modulation of the cholinergic transmission.
