Fluorescence microscopic findings on the otic and pterygopalatine ganglia of the dog

The otic and pterygopalatine ganglia and, as controls, the superior cervical ganglia of the dog were studied by the histochemical fluorescence methed of FALCK and HILLARP.Most nerve cells of the superior cervical ganglion contained monoamine specific fluorescent granules, and numerous monoaminergic terminals occurred among and around the neurons. There were, however, found neither adrenergic neurons nor adrenergic teminals in both the otic and the pterygopalatine ganglia in normal and even in nialamide-treated animals. A yellow-brown fluorescence of unknown nature, which did not disappear after the administration of reserpine as well as after cervical and upper thoracic sympathetic ganglionectomy, was found in the perikarya of nerve cells in these ganglia.The findings obtained suggest that there is no adrenergic neuron in both the otic and the pterygopalatine ganglia, and that sympathetic fibers originating from the sympathetic trunk do not make neuron exchange in the two ganglia.