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 preganglionic neurons in the lumbar and sacral spinal cord of the female rat that may underlie impaired control of the urogenital system in old age. Preganglionic sympathetic and parasympathetic neurons of young adult, aged nulliparous and aged multiparous rats were identified by retrograde tracing with cholera toxin subunit-B and subsequent immunocytochemistry. Labeled preganglionic neurons were scanned, processed and analyzed using the confocal microscope. Measurements were made of soma area, number of primary dendrites, number of dendritic branch points and total dendritic length. There were significant decreases in the number of primary dendrites, number of dendritic branch points and total dendritic length of sympathetic preganglionic neurons in both nulliparous and multiparous aged rats compared to the young adult group. No significant differences were found in the dendritic morphology of aged parasympathetic preganglionic neurons. Soma area was not significantly different between age groups for sympathetic or parasympathetic preganglionic neurons. These changes in dendritic morphology may result in altered control of the lower urogenital tract in aged nulliparous and multiparous female rats. (C) 1998 Elsevier Science B.V.