CYTOCHROME-OXIDASE STAINING IN THE MAJOR PELVIC GANGLION OF THE MALE-RAT

Cytochrome oxidase staining was used as a marker of metabolic activity in neural elements in the rat major pelvic ganglion. Many neurons in the ventral pole of the ganglion have little cytochrome oxidase activi ty, while neurons in other locations show gradations in staining inten sity. Punctate staining around principal neurons may represent pregang lionic terminals, since it was greatly reduced after denervation of th e ganglion. Image analysis was used to compare neuronal size to staini ng intensity. There was a negative correlation between cell size and s taining intensity; the largest neurons were only lightly stained for c ytochrome oxidase, while the medium and the small neurons showed a ful l range of metabolic activity. To study metabolic activity of an ident ified neuronal population, the seminal vesicles were injected with a r etrograde tracer. The largest seminal vesicles neurons (1500 to 3200 m u m(2)) had low enzyme activity, whereas the majority of neurons to th is organ were smaller with gradations in staining. These results are i ndicative of the metabolic activity of the autonomic innervation to va rious pelvic tissues. Cytochrome oxidase histochemistry should prove v aluable in assessing the demands placed on autonomic ganglia in differ ing functional and dysfunctional states. (C) 1997 Elsevier Science B.V .