Substance P- and vasoactive intestinal polypeptide (VIP)-immunoreactive nerve fibers in relation to ovarian postganglionic perikarya in para- and prevertebral ganglia: evidence from combined retrograde tracing and immunocytochemistry.

Retrograde neuronal tracing with the fluorescent dye True Blue and immunocytochemistry were utilized to examine postganglionic sympathetic neurons in para- and prevertebral ganglia projecting to the rat ovary. Perikarya in both ganglia were labeled with True Blue after application of the tracer to either the superior ovarian or ovarian plexus nerve. After application of True Blue to the superior ovarian nerve, 17% of the labeled cells in paravertebral ganglia were immunoreactive for vasoactive intestinal polypeptide. In contrast, after application of True Blue to the ovarian plexus nerve, approximately 1% of the labeled cells in paravertebral ganglia were immunoreactive for the same polypeptide. Some vasoactive intestinal polypeptide-immunoreactive perikarya in paravertebral ganglia were not labeled with True Blue. In some cases, substance P- and vasoactive intestinal polypeptide-immunoreactive fibers were closely apposed to True Blue-labeled perikarya in para- and prevertebral ganglia. Paravertebral vasoactive intestinal polypeptide-immunoreactive perikarya projecting to the ovary presumably participate directly in the control of various ovarian functions. Substance P- and vasoactive intestinal polypeptide-immunoreactive fibers closely apposed to perikarya projecting to the ovary may participate indirectly in the control of various ovarian functions by affecting the activity of ovarian postganglionic neurons.