Nerve structures of the heart and their immunohistochemical characterization in 10-week-old porcine foetuses.

The aim of the present study was to investigate the distribution of neuronal perikarya and nerve fibres and their chemical coding in the heart of 10-week-old porcine foetuses. The foetuses, obtained from a local slaughterhouse, were fixed by immersion in 4% buffered (pH 7.4) paraformaldehyde. Cryostat sections of the hearts were processed for single- or double-labelling immunofluorescence methods using antibodies against protein gene product (PGP) dopamine beta-hydroxylase (DßH), acetylcholine vesicular transporter (VAChT) and calcitonin gene-related peptide (CGRP). Numerous clusters of the PGP-positive nerve cells were observed throughout the heart wall. The majority of the clusters were found beneath the epicardium around the root of the aorta, pulmonary trunk and main veins. Some single PGP-positive neurons or small clusters of nerve cells were observed in the epicardium of heart atria and ventricles. The richest network of PGP-positive nerve fibres was observed in the base of the heart near the main cardiac blood vessel openings. Many bundles of PGP-positive nerve fibres were observed throughout the four cardiac chambers. Double-immunohistochemical staining revealed that the majority of the neurons contained immunoreactivity to VAChT, some of them stained for CGRP and the single neuronal somata were DßH-positive. The nerve fibres supplying the heart expressed immunoreactivity to DßH, VAChT or CGRP. The distribution and neurochemical coding of the nerve structures in ten-week-old foetuses are different from those observed in the hearts of juvenile pigs.

L'objectif du présent étude était d'examiner la disposition des cellules et des fibres nerveuses, ainsi que de leur codage, aux cœurs de fœtus de porc de 10 semaines. Les fœtus, obtenus dans un abattoir locale, ont été fixés par immersion dans la solution de paraformaldéhyde 4% (pH 7,4). Des coupes de cœurs, obtenues à l'aide du cryostat, ont subi une coloration immunohistochimique simple ou double afin de dépister, dans des structures nerveuses, la présence du produit génétique protéiné (PGP), de la dopamine bêta-hydroxylase (DßH), du transporteur vésiculaire de l'acétylcholine (VAChT) et du peptide relié au gène calcitonine (CGRP). De nombreuses concentrations de cellules nerveuses PGP-positives ont été observées dans la paroi cardiaque. La plupart des concentrations ont été retrouvées en dessous de l'épicarde, autour de la racine de l'aorte, du tronc pulmonaire et des veines principales. Des neurones singulaires PGP-positifs ou des petites concentrations de cellules nerveuses ont été observées dans l'épicarde des oreillettes et des ventricules du cœur. Le plus riche réseau de fibres nerveuses PGP-positives a été observé dans la base du cœur, près de l'acheminement des vaisseaux principaux. Dans les quatre chambres du cœur, de nombreux faisceaux de fibres nerveuses PGP-positives ont été observées. Des colorations immunohistochimiques doubles ont démontré que la plupart de neurones présentaient une immunoréactivité par rapport à VAChT, certains par rapport à CGRP, et des corps singulaires de cellules nerveuses étaient positives par rapport à DßH. Des fibres nerveuses alimentant le cœur présentaient une immunoréactivité par rapport à DßH, VAChT ou CGRP. La distribution et le codage neurochimique des structures nerveuses chez des fœtus de 10 semaines diffèrent de ceux observés dans les cœurs de jeunes porcs.

Effect of castration on pelvic neurons in the male pig.

The present study investigated the influence of castration performed at neonatal age on neuronal elements in the anterior pelvic ganglion of the male pig with immunohistochemistry and quantitative real-time PCR (qPCR). The ganglia were examined 3 and 6 months after surgery. In 3-month-old castrated pigs (3MCP) 74% of adrenergic and 31% of cholinergic neurons stained for caspase-3 (CASP-3), and much greater numbers of perikarya than in the control animals expressed CGRP, galanin (GAL) and VIP (peptides known to have neuroprotective properties). In 6-months-old castrated pigs (6MCP), an excessive loss (90%) of neurons and intraganglionic nerve fibres was found. The survived adrenergic and cholinergic neurons also expressed CASP-3, CGRP, GAL or VIP. The qPCR results corresponded with immunofluorescence findings. In 3MCP, genes for CASP-3 and CGRP were up-regulated, while the expression of those for DßH, VAChT, GAL, VIP and SP displayed statistically insignificant variations. In 6MCP, distinctly up-regulated were genes for CGRP, GAL, VIP, SP, DßH and VAChT, while the expression of casp3 gene was down-regulated. The study revealed for the first time the excessive loss of pelvic neurons following castration, and a realistic assumption is proposed, that the neurons died due to apoptosis triggered by androgen deprivation.

Morphological and neuroanatomical study of the mammary gland in the immature and mature European beaver (Castor fiber).

This study investigated general morphology and immunohistochemical properties of nerve fibres supplying the mammary gland (MG) in the European beaver. The microscopic analysis of the beaver mammary gland revealed the presence of morphological structures which are characteristic for mammals. There were no distinct differences in the morphological features of the mammary gland between the juvenile and non-pregnant mature beaver. The nerve fibres were visualized using antibodies against protein gene product 9.5 (PGP) and biologically active substances including ß-hydroxylase tyrosine (DßH), neuropeptide Y (NPY), calcitonine gene-related peptide (CGRP) and substance P (SP). The study has revealed that the MG in the juvenile and mature beaver is richly supplied with PGP-immunoreactive (PGP-IR) nerve fibres. The most abundant innervation was observed in the nipple and less numerous nerve terminals supplied the glandular tissue. Double-labelling immunohistochemistry disclosed that the majority of PGP-IR nerve fibres associated with blood vessels and smooth muscle cells in both the nipple and glandular tissue were also DßH-IR. However, these nerve terminals were less numerous in the glandular tissue than in the nipple. Most of the DßH-IR axons associated with arteries and smooth muscle cells in the entire gland also stained for NPY. Small number of DßH/NPY-IR fibres supplied veins. CGRP-IR fibres were more abundant than those expressing SP. No distinct differences in the distribution and immunohistochemical characteristic of nerve fibres were observed between the juvenile and adult animals. The distribution and immunohistochemical properties of nerve fibres supplying the gland in the beaver remind those previously described in other mammalian species.

The Influence of Gastric Antral Ulcerations on the Expression of Galanin and GalR1, GalR2, GalR3 Receptors in the Pylorus with Regard to Gastric Intrinsic Innervation of the Pyloric Sphincter.

Gastric antrum ulcerations are common disorders occurring in humans and animals. Such localization of ulcers disturbs the gastric emptying process, which is precisely controlled by the pylorus. Galanin (Gal) and its receptors are commonly accepted to participate in the regulation of inflammatory processes and neuronal plasticity. Their role in the regulation of gastrointestinal motility is also widely described. However, there is lack of data considering antral ulcerations in relation to changes in the expression of Gal and GalR1, GalR2, GalR3 receptors in the pyloric wall tissue and galaninergic intramural innervation of the pylorus. Two groups of pigs were used in the study: healthy gilts and gilts with experimentally induced antral ulcers. By double immunocytochemistry percentages of myenteric and submucosal neurons expressing Gal-immunoreactivity were determined in the pyloric wall tissue and in the population of gastric descending neurons supplying the pyloric sphincter (labelled by retrograde Fast Blue neuronal tracer). The percentage of Gal-immunoreactive neurons increased only in the myenteric plexus of the pyloric wall (from 16.14±2.06% in control to 25.5±2.07% in experimental animals), while no significant differences in other neuronal populations were observed between animals of both groups. Real-Time PCR revealed the increased expression of mRNA encoding Gal and GalR1 receptor in the pyloric wall tissue of the experimental animals, while the expression(s) of GalR2 and GalR3 were not significantly changed. The results obtained suggest the involvement of Gal, GalR1 and galaninergic pyloric myenteric neurons in the response of pyloric wall structures to antral ulcerations.

Differences in the chemical coding of nerve fibres supplying major populations of neurons between the caudal mesenteric ganglion and anterior pelvic ganglion in the male pig.

The present study was designed to investigate and to compare the chemical coding of nerve fibres supplying major populations of neurons in the caudal mesenteric (CaMG) and anterior pelvic (APG) ganglion in juvenile male pigs (n=5) using double-labelling immunofluorescence. The co-existence patterns of some biologically active substances including tyrosine hydroxylase (TH) and vesicular acetylcholine transporter (VAChT) as well as vasoactive intestinal polypeptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), Leu5-enkephalin (LENK) and serotonin (5-HT) were analysed under a confocal laser scanning microscope. Profound differences in the neurochemical features of the nerve terminals between the ganglia were observed. Moreover, there were also distinct differences in the chemical coding of nerve fibres associated with the particular populations and subpopulations of neurons within the ganglia. In both ganglia, nearly all adrenergic and cholinergic neurons were supplied with VAChT-positive nerve fibres (putative preganglionic fibres). However, in the CaMG, they were more numerous and, in contrast to the APG, many of them also stained for VIP. In the APG, a great number of nerve terminals expressed immunoreactivity to SP and CGRP (putative collaterals of sensory neurons). Interestingly, they densely supplied almost exclusively adrenergic neurons. SP-positive nerve fibres were moderate in number in the CaMG, but, in addition to VAChT-IR nerve terminals, the most numerous populations of nerve fibres in this ganglion were those expressing highly colocalized immunoreactivities to CGRP and LENK, and those which stained for 5-HT (putative processes of enteric neurons). However, these fibres supplied almost exclusively larger, intensely stained for TH and clustered adrenergic neurons. This diversity of the nerve terminals reflects the complexity of nerve circuits involved in the innervation of structures supplied by neurons in the porcine CaMG and APG. It also demonstrates the importance of nerve inputs for the proper function of autonomic neurons and thus their target tissues.

Immunohistochemical characterisation of cholinergic neurons in the anterior pelvic ganglion of the male pig.

This study investigated immunohistochemical properties of cholinergic neurons in the anterior pelvic ganglion (APG) of juvenile male pigs (n=7). Cholinergic neurons were identified using antibodies against choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT). Immunoblotting was applied to verify the specificity of ChAT-immunostaining. Western blotting performed on APG tissue homogenates detected single immunoreactive protein with a molecular weight matching that of ChAT (71.6 kDa). It was found that many APG neurons expressed immunoreactivity to ChAT or VAChT (40% and 39% of the neurons, respectively). The analysis of adjacent sections from the ganglion revealed complete colocalization of ChAT and VAChT in these nerve cells. Furthermore, virtually all the ChAT-positive neurons were tyrosine hydroxylase (TH)-negative (non-adrenergic) but many of them displayed immunoreactivity to nitric oxide synthase (NOS), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) or somatostatin (SOM). There were also single nerve cell bodies that stained for neither ChAT nor TH. The comparison of the adjacent sections revealed that NOS, VIP, NPY and SOM were simultaneously co-expressed in the majority of the cholinergic somata. ChAT- or VAChT-positive varicose nerve terminals supplied nearly all neuronal profiles within the ganglion often forming loose basket-like formations surrounding the particular nerve cell bodies. The present study for the first time has revealed that nearly all non-adrenergic neurons in the porcine APG are cholinergic in nature, i.e. express immunoreactivity for ChAT and VAChT. Considering a high coincidence between the chemical coding of non-adrenergic (cholinergic) nerve fibres supplying some porcine male reproductive organs described in earlier papers and that of cholinergic pelvic neurons found in this study it is further concluded that pelvic ganglia are probably the major source of cholinergic innervation for the porcine urogenital system.

Noradrenergic and peptidergic innervation of the mammary gland in the immature pig.

The presence and pattern of coexistence of some biologically active substances in nerve fibres supplying the mammary gland in the immature pig were studied using immunohistochemical methods. The substances studied included: protein gene product 9.5 (PGP), tyrosine hydroxylase (TH), somatostatin (SOM), neuropeptide Y (NPY), galanin (GAL), calcitonin gene-related peptide (CGRP) and substance P (SP). The mammary gland was found to be richly supplied by PGP-immunoreactive (PGP-IR) nerve fibres that surrounded blood vessels, bundles of smooth muscle cells and lactiferous ducts. The vast majority of these nerves also displayed immunoreactivity to TH. Immunoreactivity to SOM was observed in a moderate number of nerve fibres which were associated with smooth muscles of the nipple and blood vessels. Immunoreactivity to NPY occurred in many nerve fibres associated with blood vessels and in single nerves supplying smooth muscle cells. Solitary GAL-IR axons supplied mostly blood vessels. Many CGRP-IR nerve fibres were associated with both blood vessels and smooth muscles. SP-IR nerve fibres richly supplied blood vessels only. The colocalization study revealed that SOM, NPY and GAL partly colocalized with TH in nerve fibres supplying the porcine mammary gland.

Distribution of ganglionic sympathetic neurons supplying the subcutaneous, perirenal and mesentery fat tissue depots in the pig.

Previous morphological studies revealed that the adipose tissue is innervated by adrenergic nerve fibers. Furthermore, physiological studies showed that the metabolism of adipose tissue is controlled by the adrenergic component of the nervous system. However, nothing is known on the sources of innervation of different fat tissue depots. Therefore, we decided to study the distribution of ganglionic sympathetic neurons innervating adipose tissue in the pig by means of a retrograde tracing method. We used 9 male and 9 female pigs of approximately 50 kg body weight. The retrograde tracer, Fast Blue (FB), was injected into the subcutaneous, perirenal and mesentery fat tissue depots. Results of the present study showed that numerous centers of the sympathetic nervous system innervate adipose tissue in the pig. FB+ neurons projecting to the subcutaneous fat tissue were placed in the thoraco-lumbar region of the sympathetic chain ganglia (SChG). However, neurons supplying perirenal and mesentery fat tissue depots were found in both the SChG and prevertebral ganglia (PVG). We conclude that different adipose tissue depots (subcutaneous, perirenal and mesentery) have different sources of innervation and that there is no significant difference in the distribution of neurons innervating adipose tissue in male and female pigs.