Quantitative analysis of development and aging of genital corpuscles in glans penis of the rat.

The aim of the present postnatal developmental study was to determine densities of unique genital corpuscles (GCs) in glans penis of developing and aged rats. GCs were identified as corpuscular endings consisting of highly branched and coiled axons with many varicosities, which were immunoreactive for protein gene product 9.5. In addition, GCs were immunoreactive for calcitonin gene-related peptide and substance P, but not for vasoactive intestinal polypeptide and neuropeptide Y. GCs were not found in the glans penis of 1 week old rats. Densities of GCs were low at 3 weeks, significantly increased at 5 and 10 weeks, reached the peak of density at 40 weeks, and tended to decrease at 70 and 100 weeks. Sizes of GCs were small in 3 weeks old rats, increased at 5 and 10 weeks, reached the peak-size at 40 weeks and reduced in size at 70 and 100 weeks. Considering sexual maturation of the rat, the results reveal that GCs of the rat begins to develop postnatal and reaches to the peak of their development after puberty and continues to exist until old age, in contrast to prenatal and early postnatal development of other sensory receptors of glabrous skin.