Differential distribution of small and large neurons in the sacrococcygeal dorsal root ganglia of the cat.
The differential distribution of small and large neurons in the sacrococcygeal dorsal root ganglia of the cat was disclosed by measuring the short diameter of the perikarya. The measured values were systematically charted along the rostro-caudal axis of the ganglion. This approach permitted to delineate small and large neurons; the short diameter of the former being less, that of the latter more, than 22 micrometers. Small neurons (69% of the population) are distributed along the entire length of the ganglions, while large neurons are clustered in the distal half. The same histological specimens were appropriate to show that if only every 8th section was used for counting the number of perikarya (the number of the nucleoli was interpreted as that of the perikarya) the result was not significantly different (less than +/- 5%) from that gained by a total count. The significance of the inhomogeneous distribution of ganglion cells was discussed within the emerging concept of the topological arrangement of the perikarya in the ganglion, on the one hand, and the termination of the central branch of the neurons in the spinal cord, on the other.
D000818:Animals; D002415:Cats; D002466:Cell Nucleolus / Q000648:ultrastructure; D005727:Ganglia, Spinal / Q000166:cytology*; D009474:Neurons / Q000166:cytology*; D012445:Sacrococcygeal Region