Histochemical study, morphometric analysis and systematic distribution of fiber types in the rectus femoris muscle of the albino rats.

The histochemical and morphometric characteristics as well as the systematic distribution of fiber types in the muscle rectus femoris (RF) of adult male rats were studied from ATPase (pre-incubated at pH 9'4, 4'6 and 4'2) and NADH stained sections. The muscle fiber types were classified as I type, IIA type and IIB-type. In 20 RF muscles 90-95% of total fibers were sampled and the mean diameter, length and irregularity-degree analysed. The data were grouped in four quadrants and the percent of fiber types was determined. The type IIB fibers predominate in all quadrants. The largest fibers were the IIB type and the smallest ones the type I, for all the quadrants. Our findings support a functional compartmentalization as proposed by many authors.

[Innervation of the ventral prostate of the rat: ultrastructural study]. / Inervación de la próstata ventral de la rata: estudio ultraestructural.

The innervation of the rat ventral prostate was studied at the ultrastructural level. The nerve fascicles, amyelinics, are found in the interstitial tissue of the gland. We have observed varicosities with synaptic vesicles in close contact with the smooth muscle and epithelial cells. Inside the nerve endings, 5 types of vesicles could be distinguished. The role of the different nerve endings is discussed.