NUMBER, SIZE, AND REGIONAL DISTRIBUTION OF MOTOR-NEURONS IN THE DORSOLATERAL AND RETRODORSOLATERAL NUCLEI AS A FUNCTION OF SEX AND NEONATALSTIMULATION

Motor neurons were measured in the retrodorsolateral nucleus (RDLN) an d the dorsolateral nucleus (DLN) of adult male and female rats that we re reared with normal or reduced levels of maternal anogenital stimula tion. In contrast with findings for the spinal nucleus of the bulbocav ernosus, which is located In the same spinal segments, reduced stimula tion had no effect on neuron number in either nucleus. However, severa l regional and sex differences were observed. Rostrally located neuron s were larger in both the RDLN and the DLN; these location effects wer e greater in females. There was no sex difference in RDLN neuron size, but DLN neurons were larger in females, particularly in the rostral r egion. Females had significantly more cells in the RDLN, a nucleus pre viously considered nondimorphic, whereas males had more DLN neurons. B oth regional and sex differences may reflect local differences in trop hic factors from targets or afferents. (C) 1996 John Wiley & Sons, Inc . & Sons, Inc.