AGE-RELATED-CHANGES IN THE MORPHOLOGY OF PREGANGLIONIC NEURONS PROJECTING TO THE PARACERVICAL GANGLION OF NULLIPAROUS AND MULTIPAROUS RATS

The aim of this study was to investigate age-related changes in pregan glionic neurons in the lumbar and sacral spinal cord of the female rat that may underlie impaired control of the urogenital system in old ag e. Preganglionic sympathetic and parasympathetic neurons of young adul t, aged nulliparous and aged multiparous rats were identified by retro grade tracing with cholera toxin subunit-B and subsequent immunocytoch emistry. Labeled preganglionic neurons were scanned, processed and ana lyzed using the confocal microscope. Measurements were made of soma ar ea, number of primary dendrites, number of dendritic branch points and total dendritic length. There were significant decreases in the numbe r of primary dendrites, number of dendritic branch points and total de ndritic length of sympathetic preganglionic neurons in both nulliparou s and multiparous aged rats compared to the young adult group. No sign ificant differences were found in the dendritic morphology of aged par asympathetic preganglionic neurons. Soma area was not significantly di fferent between age groups for sympathetic or parasympathetic pregangl ionic neurons. These changes in dendritic morphology may result in alt ered control of the lower urogenital tract in aged nulliparous and mul tiparous female rats. (C) 1998 Elsevier Science B.V.