Immunohistochemical localization of Met5-enkephalin-Arg6-Gly7-Leu8 in the female genital organs and in the paracervical ganglion of the pig

Effect of partial hysterectomy on the neurons of the paracervical ganglion (PCG) of the pig

Autonomic neurons innervating uterine horn is probably the only nerve cell population capable of periodical physiological degeneration and regeneration. One of the main sources of innervation of the uterus is paracervical ganglion (PCG). PCG is a unique structure of the autonomic nervous system. It contains components of both the sympathetic and parasympathetic nervous system. The present study examines the response of neurons of PCG innervating uterine horn to axotomy caused by partial hysterectomy in the domestic pig animal model. The study was performed using a neuronal retrograde tracing and double immunofluorescent staining for tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DβH), choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), neuronal nictric oxide synthase (nNOS), galanin, neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating peptide (PACAP), somatostatin and substance P (SP). Our study showed that virtually all neurons of the porcine PCG innervating uterine horn are adrenergic and we did not confirm that PCG is the source of cholinergic fibers innervating uterine horn of the pig. After axotomy there was a decrease in expression of catecholamine-synthesizing enzymes (TH, DβH) and a strong increase in the galanin expression. The increase of the number of NPY-IR neurons in the ganglia after axotomy was observed. There were no changes in the expression of other studied substances in the PCG neurons innervating the uterine horn, what was often found in rodents studies. This indicates that neurons can respond to damage in a species-specific way.

Upregulation of LENK and VIP in paracervical ganglion neurons supplying the urinary bladder of tetrodotoxin- and resiniferatoxin-treated female pigs

Both resiniferatoxin (RTX) and tetrodotoxin (TTX) have been reported to be effective in several clinical trials aiming to cure urinary bladder dysfunction. The goal of this experiment was to study the effect of intravesical administration of RTX and TTX on the chemical coding of paracervical ganglion (PCG) neurons that supply the urinary bladder in pigs. The vasoactive intestinal peptide (VIP) and the opioid family member Leu5-enkephalin (LENK) are both known for their regulatory effects in the function of the porcine genitourinary tract. The PCG neurons innervating the urinary bladder were identified by application of the retrograde tracer Fast Blue (FB), injected into the bladder wall prior to intravesical RTX or TTX administration. Immunocytochemical detection of LENK and VIP expression in the FB-labelled perikarya revealed that in the control group 25.15% of the FB-positive PCG neurons contained LENK, and 9.22% of them expressed VIP. Intravesical infusion of RTX resulted in an increase in the number of LENKIR neurons to 48.19% and VIP-IR perikarya to 11.25%. Optional treatment with TTX induced increase of LENK-IR neurons up to 81.67% and VIP-IR population to 16.46% of the FB-positive PCG cells. The present results show that both neurotoxins affect the chemical coding of PCG nervous cells supplying the porcine urinary bladder and that they stimulate both LENK and VIP expression. Furthermore, the results indicate a possible involvement of LENK and VIP neurons in the mechanisms of action of RTX and TTX in the therapy of overactive bladder disorder.

Uterus-innervating neurones in porcine inferior mesenteric ganglion: an immunohistochemical characteristic

The presence of tyrosine hydroxylase, neuropeptide Y, vasoactive intestinal polypeptide, galanin, Met-enkephalin-Arg-Gly-Leu, substance P and calcitonin gene-related peptide was studied with immunohistochemistry in uterus-innervating neurones found in the inferior mesenteric ganglia after fluorescent tracer (Fast Blue) injection into different regions of the porcine uterus (uterine cervix, paracervical, middle and paraoviductal part of the uterine horn). Virtually all Fast Blue-positive neurones found in the inferior mesenteric ganglia after tracer injection into all studied parts of the uterus contained tyrosine hydroxylase and ca. 45% of them contained neuropeptide Y. Single galanin-positive/Fast Blue-positive cells were found in the ganglia only after tracer injections into uterine cervix. No other studied substances were found in the Fast-Blue positive neurones of the inferior mesenteric ganglia.

Peptidergic innervation of the bovine vagina and uterus

The distribution of neuropeptide Y, substance P, vasoactive intestinal polypeptide, Leu5-enkephalin, bombesin/gastrin-releasing peptide, calcitonin gene-related peptide, somatostatin, cholecystokinin and catecholamine synthesizing enzymes, tyrosine hydroxylase and dopamine-beta-hydroxylase was studied immunohistochemically in nerve fibres supplying the bovine vagina and uterus. The nerves containing tyrosine hydroxylase or dopamine-beta-hydroxylase and neuropeptide Y-immunoreactivity were particularly numerous in both organs. Substance P, vasoactive intestinal polypeptide and Leu5-enkephalin-containing nerves were less numerous whereas somatostatin and calcitonin gene-related peptide-immunoreactive nerves occurred occasionally. Bombesin/gastrin-releasing peptide and cholecystokinin immunoreactivities were not present in nervous fibers of the bovine uterus and vagina. Generally, the immunoreactive nerve terminals, fibers, networks or nerve bundles were present below the serous membrane, between smooth muscle cells of muscular layers, around blood vessels, in the submucosal layer and below the luminal epithelium of the uterus and cervix.