A light and electron microscopic study of feline intrapulmonary ganglia.

Fluorescence microscopy and transmission electron microscopy were used to study peribronchial ganglia of cats. An osmiophilic substance that is selectively taken up into the synaptic vesicles of adrenergic nerves (5-hydroxydopamine) was used to help differentiate adrenergic and non-adrenergic terminals. Peribronchial ganglion cells show no catecholamine fluorescence and are unaffected by 5-hydroxy-dopamine. There are three types of efferent terminals in the ganglia: cholinergic terminals, terminals with small agranular round and flat vesicles and terminals that contain large dense-core vesicles as well as small vesicles and tubules that take up 5-hydroxydopamine. Clusters of SIF cells are associated with some peribronchial ganglia. It is suggested that peribronchial ganglion cells integrate synaptic input from two or three types of nerve terminals and may also be affected by catecholamines released into the bronchial vascular system by SIF cells.