Effect of total or partial uterus extirpation on uterus-projecting neurons in porcine inferior mesenteric ganglion. A. Changes in expression of transmitter-synthesizing enzymes--tyrosine hydroxylase, dopamine beta-hydroxylase and choline acetyltransferase.

Expression of tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH) and choline acetyltransferase (ChAT) was studied with immunohistochemistry, in situ hybridization, RT-PCR and immunoblotting in two populations of neurons of porcine inferior mesenteric ganglion (IMG) projecting to the uterine horn and uterine cervix after axotomy induced by partial or total uterus extirpation in sexually immature gilts. Uterus-projecting neurons of the IMG were identified by retrograde tracing with Fast Blue. Additionally, the distribution of ChAT-positive (ChAT+) and Met-enkephalin-positive (ME+) nerve fibers around uterus-projecting neurons was studied with immunohistochemistry. Immunohistochemistry detected that extirpation-induced axotomy reduced dramatically TH, but not DBH, expression in the uterus-projecting neurons, while the expression level of ChAT remained unchanged. Hybridization in situ performed with molecular probes for TH and ChAT confirmed these findings. RT-PCR did not detect any changes in the expression of TH and ChAT at mRNA level between control and hysterectomized animals. Immunoblotting did not detect significant changes in the expression of TH and DBH in IMG after partial or total extirpation. However, it detected that after total extirpation of the uterus a new form of ChAT with apparent lower molecular mass appears in the IMG of hysterectomized animals. It was found also that the number of ChAT+ and ME+ nerve fibers is lower around axotomy-affected neurons than around neurons in control gilts. The results presented here show clear axotomy-associated changes in the expression of TH, but not DBH and ChAT in the uterus-projecting neurons of the porcine IMG, as well as changes in the expression of ChAT and ME in the preganglionic nerve fibers.