Endometritis Changes the Neurochemical Characteristics of the Caudal Mesenteric Ganglion Neurons Supplying the Gilt Uterus

This study analyzed the influence of uterine inflammation on the neurochemical characteristics of the gilt caudal mesenteric ganglion (CaMG) uterus-supplying neurons. The horns of uteri were injected with retrograde tracer Fast Blue on day 17 of the first studied estrous cycle. Twenty-eight days later (the expected day 3 of the third studied estrous cycle), either saline or Escherichia coli suspension were administered into each uterine horn. Only the laparotomy was done in the control gilts. After 8 days, the CaMGs and uteri were harvested. The infected gilts presented a severe acute endometritis. In the CaMGs, the populations of uterine perikarya possessing dopamine-β-hydroxylase (DβH) and/or neuropeptide Y (NPY), somatostatin (SOM), galanin (GAL) and vasoactive intestinal polypeptide (VIP) were analyzed using the double immunofluorescence method. In the CaMG, bacterial injection decreased the total number of the perikarya (Fast Blue-positive), the small and large perikarya populations in the dorsal and central regions, and the small and large perikarya populations coded DβH+/GAL- and DβH-/NPY+. After bacterial treatment, there was an increase in the numbers of small and large perikarya coded DβH+/NPY+, small perikarya coded DβH+/GAL+ and DβH+/SOM- and large perikarya coded DβH+/VIP+. To summarize, uterine inflammation influences the neurochemical characteristics of the CaMG uterus-supplying neurons, which may be important for pathologically changed organ functions.

Distribution and immunohistochemical properties of autonomic neurons supplying the ovine hip joint capsule

Combined retrograde tracing and double labelling immunohistochemistry were applied to study the distribution and chemical coding of autonomic neurons projecting to the ovine hip joint capsule. As revealed by retrograde tracing, fast blue-positive autonomic neurons supplying the lateral side of the hip joint capsule and the medial side of the hip joint capsule were located within the lumbar and sacral of the ipsilateral sympathetic chain ganglia and within the caudal mesenteric ganglion. Immunohistochemistry revealed that nearly all (sympathetic chain ganglia: 96% and caudal mesenteric ganglion: 98.8%) the neurons were adrenergic in nature (positive for dopamine β-hydroxylase). Many retrogradely labelled neurons also displayed immunoreactivity to neuropeptide Y (approximately 34% of fast blue-positive neurons within caudal mesenteric ganglion and sympathetic chain ganglia). Populations of Met-Enk⁺ (20%) and Leu-Enk⁺ (6%) neurons were present only in the sympathetic chain ganglia while within caudal mesenteric ganglion no enkephalinergic-labelled neurons were noted. Only a small population (2.2%) of hip joint capsule-projecting neurons were Gal-IR and they were observed only within the caudal mesenteric ganglion. No cholinergic neurons involved in the innervation of the hip joint capsule were found. However, fast blue-positive nerve cell bodies were surrounded by numerous cholinergic nerve fibres often forming basket-like formations. Single Gal⁺ nerve fibres were found in the intraganglionic connective tissue. Substance P-positive or calcitonin gene-related peptide-positive intraganglionic nerve terminals were very numerous and formed “baskets” surrounding fast blue-positive perikarya within sympathetic chain ganglias and caudal mesenteric ganglion.

Caudal mesenteric ganglion in the sheep – macroanatomical and immunohistochemical study

The caudal mesenteric ganglion (CaMG) is a prevetrebral ganglion which provides innervation to a number of organs in the abdominal and pelvic cavity. The morphology of CaMG and the chemical coding of neurones in this ganglion have been described in humans and many animal species, but data on this topic in the sheep are entirely lacking. This prompted us to undertake a study to determine the localization and morphology of sheep CaMG as well as immunohistochemical properties of its neurons. The study was carried out on 8 adult sheep, weighing from 40 to 60 kg each. The sheep were deeply anaesthetised and transcardially perfused with 4% paraformaldehyde. CaMG-s were exposed and their location was determined. Macroanatomical observations have revealed that the ovine CaMG is located at the level of last two lumbar (L5 or L6) and the first sacral (S1) vertebrae. The ganglion represents an unpaired structure composed of several, sequentially arranged aggregates of neurons. Immunohistochemical investigations revealed that nearly all (99.5%) the neurons were DβH-IR and were richly supplied by VACHT-IR nerve terminals forming „basket-like” structures around the perikarya. VACHT-IR neurones were not determined. Many neurons (55%) contained immunoreactivity to NPY, some of them (10%) stained for Met-ENK and solitary nerve cells were GAL-positive. CGRP-IR nerve fibres were numerous and a large number of them simultaneously expressed immunoreactivity to SP. Single, weakly stained neurones were SP-IR and only very few nerve cells weakly stained for VIP.

Distribution and chemical coding of sympathetic neurons in the caudal mesenteric ganglion projecting to the ovary in sexually mature gilts

The distribution and co-localisation patterns of dopamine-β-hydroxylase (DβH), neuropeptide Y (NPY), somatostatin (SOM) and galanin (GAL) were investigated by use of retrograde neuronal tracing and double-labelling immunofluorescence techniques in the caudal mesenteric ganglion (CaMG) neurons supplying the ovary of adult pigs. The existence and density of nerve fibres that are immunoreactive (IR) for the above-mentioned neuroactive substances were also evaluated. Injections of a fluorescent tracer (Fast Blue; FB) into the ovaries revealed the presence of small- (76.38%) and large-sized (23.62%) FB-positive postganglionic neurons in the CaMG. Noradrenergic FB-positive cells were simultaneously NPY- (43.38%), SOM- (18.77%) and GAL- (18.31%) IR. Of the examined FB-positive neurons, 53.49% were DβH-IR but NPY-immunonegative (IN), 79.06% were DβH-IR but SOM-IN, and 77.16% were DβH-IR but GAL-IN. Small- or large-sized subsets of traced neurons were supplied by only one or a few nerve fibres, exhibiting DβH-, NPY-, SOM- and/or GAL-IR. Our data show the specific morphological as well as immunochemical structural organisation of the sympathetic neurons in the CaMG in adult gilts. The occurrence of an abundant population of noradrenergic perikarya in the CaMG may suggest their important physiological role in the regulation of gonadal function(s) in these animals.