Abstract
The dog carotid body was studied by light and electron microscopy. It consisted of small clumps of glomus cells, interspersed between blood vessels. The glomus cells were classified into chromaffin and nonchromaffin cells, on the basis of their light microscopic reaction to potassium dichromate. The chromaffin cells were more infrequent in occurrence and their cytoplasm was filled with intensely osmiophilic granules of various sizes and irregular shapes, while the nonchromaffin cells were predominant in number and their specific granules were more uniform in structure and showed moderate osmiophilia. It was remarked that the chromaffin and nonchromaffin cells of the carotid body respectively correspond in their fine structure to the noradrenalin and adrenalin storing cells of the adrenal medulla, and the possible secretory function of the glomus cells was discussed. The light microscopically “negative” chromaffin reaction in a part of glomus cells may not necessarily indicate the absence of catecholamines but a low value of them in these cells.
Nerve endings occurred frequently on the glomus cells. They resemble in fine structure the nerve endings to the adrenal medullary cells. The synaptic vesicles were present on the neural side of the synapse and it was concluded that the glomus cells receive an efferent innervation. Besides the ordinary spherical, synaptic vesicles of flattened shape were recognized which may possibly be of an inhibitory nature, if the hypothesis of UCHIZONO be applicable in the glomus innervation.
Ganglion cells were found sporadically, in the interlobular connective tissue.
