This study was directed to identify neurons in the spinal cord and brainstem that could participate in circuits for innervation of the uterus and be responsive to estrogen. Transsynaptic retrograde axonal tracing, using pseudorabies virus (PRV), in combination with estrogen receptor (ER) immunohistochemistry was used to examine the location of cell bodies of uterine-related neurons that are and expressing ER protein. The uterine cervix, body and proximal uterine horns were injected at multiple sites with PRV (total of 6 μl of 2×107 pfu/ml) and then the rats were ovariectomized (ovex). Rats were killed 5 days later. Double label Immunohistochemistry was performed on sections of aldehyde-fixed spinal cords and brainstems using a swine generated antisera against PRV and a rat generated antibody against ER. PRV labeling was prevalent in the sacral parasympathetic nucleus (SPN), in lamina X and across lamina VII betwen the latter two sites. PRV-labeled neurons were evident in the nucleus tractus solitarius (NTS), ventrolateral medulla, scattered in the retcular formation and in Barrington's nucleus of the brainstem. ER-positive neurons were frequent among the uterine-related PRV-positve neurons of the SPN and lamina X. To date, ER-positive neurons have been evidenced among PRV-positive neurons in the NTS but, they are few. Occasional spinal neurons appear to contain both PRV and ER-immunoreactivity. These data suggest there are neurons in CNS visceral nuclei which are involved in circuits that ultimately innervate the uterus and some of these could be responsive to circulating estrogen.
|State||Published - 1 Dec 1997|