Histochemical and biochemical characterization of the rat paracervical ganglion.

The nature and identity of the catecholamines in the paracervical ganglion and superior cervical ganglion small, intensely fluorescent (SIF) cells were investigated using fluorescence histochemical and immunohistochemical techniques. The paracervical ganglion SIF cells were found to contain norepinephrine and the superior cervical ganglion SIF cells, dopamine. The norepinephrine content of the paracervical ganglion SIF cells averaged about 72 ng/ganglion and did not change during the rat estrus cycle. The activity of the enzyme tyrosine hydroxylase in the PCG was very low (about 0.48 nmoles DOPA formed/h/mg protein) and was about 1/50th of the activity of the enzyme in the SCG, where it averaged about 23.90 nmoles DOPA formed/h/mg protein. These experiments suggested that the paracervical ganglion has large numbers of norepinephrine containing SIF cells with a relatively slow turnover of their catecholamine content.