ONTOGENY OF NEUROTRANSMITTER SYSTEMS IN THE PARACERVICAL GANGLION ANDUTERINE CERVIX OF THE RAT

Background: The paracervical ganglia (PG) are components of the pelvic plexus that provides sensory and motor innervation to the reproductiv e system of the female rat. Several neurotransmitters including norepi nephrine (NE), acetylcholine (ACh), neuropeptide Y (NPY), and vasoacti ve intestinal polypeptide (VIP) are present in neurons of the adult PG and in axons innervating the adult uterus and uterine cervix. The cur rent study was undertaken to describe the onset of immunoreactivity of these neurotransmitters and neuropeptides during development. Methods : Female rats, ages E18 to P36, were prepared for immunohistochemistry for TH (tyrosine hydroxylase, a marker of noradrenergic neurons), NPY , or VIP as well as the histochemical demonstration of acetylcholinest erase (AChE). Results: All four markers were detected in neurons of th e PG at E18. Changes in the appearance of these markers from E18 to P3 6 reflected previously described growth changes in the PC;. Axons cont aining AChE, TH, NPY, or VIP were first detected within the cervix at E20. Immunopositive axons first appeared as thick, unbranched structur es at the outermost portion of the cervical myometrium. Over time, the se axon bundles ramified to form discrete varicose axons. The ingrowth was similar for axons containing each of the four markers. Conclusion s: The relative density of each neuronal type in the PG was reflected in the density of axons containing the same marker in the cervix. Chan ges in neurotransmitter/neuropeptide staining of PG; neurons or axons in the cervix were not observed as the animals approached puberty. (C) 1994 Wiley-Liss, Inc.