Paraganglia of the superior laryngeal nerve of the rat.

Paraganglia were consistently found at the bifurcation of the superior laryngeal nerve of the rat. Ultrastructurally the paraganglionic cells resembled the type I and type II cells of the carotid body. The dense-cored vesiculated type I cell was found most frequently, whereas the type II cell represented 10-25% of the cell population. The volume density of the dense-cored vesicles was found to be 3.5 +/- 0.5, which is about half as much as that found in the recurrent laryngeal nerve and about twice of that found in the carotid body. A total of 24,634 dense-cored vesicles were measured, and the mean diameter was calculated to be 113.8 +/- 4.9 nm. Based on the median vesicle profile diameter, only one type of dense-cored vesicle cell was found.