Sympatho--adrenergic neural control of the sphincter of Oddi of the cat and the dog.

The presence of adrenergic axons within the sphincter of Oddi of the cat and dog was demonstrated using the glyoxylic acid-induced fluorescence histochemical method. After vagotomy (in cats), no reduction was observed in the number of the adrenergic axons or in the fluorescence intensity. It is concluded that the sphincter of Oddi receives direct adrenergic neural control derived from the sympathetic plexuses and ganglia, whereas the vagal contribution of adrenergic axons is negligible, if it exists at all.