Demonstration of paracervical ganglion origin for the vasoactive intestinal peptide-containing nerves of the rat uterus using retrograde tracing techniques combined with immunocytochemistry and denervation procedures

The origin of the abundant vasoactive intestinal peptide (VIP)-immunoreactive nerves in the uterus has not been fully determined. In this study, a fluorescent dye, True Blue was injected into the uterus of rat and 6 days later, neuronal cell bodies of the paracervical ganglion were found to be labelled by this dye. Some of these labelled ganglion cells were also found to contain VIP immunoreactivity by immunocytochemistry. When the preganglionic pelvic and/or hypogastric nerves of rats were sectioned, the VIP-immunoreactive nerves in the uteri were not depleted, indicating that these nerves did not originate from the splanchnic ganglion, dorsal root ganglion or the spinal cord. Therefore it is concluded that VIP-immunoreactive nerves in the uterus originate from the paracervical ganglion.

Peptide-containing nerves in human urinary bladder

Nerves containing immunoreactive vasoactive intestinal polypeptide (VIP), substance P and two newly discovered peptides, neuropeptide tyrosine (NPY) and PHI (peptide having N-terminal histidine and C-terminal isoleucine), have been found in the human urinary bladder by immunocytochemistry and radioimmunoassay. Somatostatin immunoreactivity was detected by radioimmunoassay. The VIP-immunoreactive nerves were widely distributed in all regions, but were particularly dense beneath the epithelium and in the muscle layer. Scattered intramural ganglia were found to be reactive to VIP antiserum. Higher concentrations of extractable VIP were detected in the trigone than in the dome. VIP- and PHI-immunoreactive nerves were similarly distributed, the latter being less numerous. NPY-immunoreactive nerves were seen mainly in the muscle layer, particularly in the trigonal area. The distribution patterns of VIP- and NPY-immunoreactive nerves resembled those of the previously reported cholinergic and adrenergic nerves, respectively. Many blood vessels were found to be innervated by both types of immunoreactive nerves. Scattered substance P-immunoreactive fibers were occasionally seen, being present in the submucosa and around the detrusor muscles. The significance of these nerves remains to be elucidated.

Neuropeptide Y in the guinea-pig biliary tract

High concentrations of neuropeptide Y (NPY) have been demonstrated in the gall bladder (16.7 +/- 5.4 pmol/g), cystic duct (25.4 +/- 9.2 pmol/g) and common bile duct (54.7 +/- 11.5 pmol/g) of the guinea-pig using a recently developed radioimmunoassay. Immunoreactive NPY containing nerves were demonstrated in all layers of the biliary tree using immunocytochemistry, being particularly dense in the myenteric and mucosal plexuses.

Decrease of vasoactive intestinal polypeptide (VIP) in the penises from impotent men

Vasoactive intestinal polypeptide (VIP)-containing nerves were depleted in the penises of 28 impotent men. The extent of the decrease in VIP-containing nerves broadly reflected the severity of erectile dysfunction. VIP-immunoreactive nerves were most depleted in those men with complete erectile impotence, irrespective of the aetiology of the dysfunction, whereas in those men in whom some erectile function persisted, loss of VIP-immunoreactive nerves was more variable and less complete. Conventional histology demonstrated only mild changes (muscle atrophy and occasional thickening of blood vessel walls). VIP levels, measured by radioimmunoassay of tissue extracts, were depleted by more than 80% in penises from impotent diabetics (43.4 +/- 9.9 pmol/g wet weight [mean +/- SEM]), when compared with 6 controls (189.9 +/- 45.9 pmol/g). These findings not only support the contention that VIP may be the principal neurotransmitter involved in penile erection, but also suggest that depletion of this powerful vasodilatory peptide may play a key role in the development of penile impotence.

High concentrations of a novel peptide, neuropeptide Y, in the innervation of mouse and rat heart

A newly discovered bioactive peptide, neuropeptide Y (NPY), has been found in the innervation of the mouse and rat heart by immunocytochemistry, NPY-immuno-reactive nerves were very dense around the nodal tissues. They also surrounded the coronary arteries and arterioles and were found in close association with the cardiac muscle. The distribution of NPY-containing nerves paralleled that of noradrenergic fibers, demonstrated by the use of antibodies to the catecholamine-converting enzymes tyrosine hydroxylase and dopamine beta-hydroxylase. Furthermore, NPY was seen to be present in a proportion of intrinsic neurons mostly found in the atria and in close proximity to the nodal tissue. The concentrations of extractable NPY-immunoreactive material (about 150 pmol/g in whole mouse heart) by far surpasses those of the other peptides so far reported in the cardiac tissue. High performance liquid chromatography demonstrated the NPY immunoreactivity to elute in a single sharp peak, in an identical position to brain NPY.

The origin of VIP-containing nerves in the urinary bladder of rat

The innervation of the urinary bladder is known to include a considerable number of nerves containing vasoactive intestinal polypeptide (VIP). The origin of such nerves in the bladder of rat was investigated in this study using the methods of immunocytochemistry and radioimmunoassay combined with surgical sectioning of the hypogastric and/or pelvic nerves to the bladder. Eight days after pelvic nerve sectioning proximal to the main pelvic ganglion, VIP-immunoreactive nerves and VIP content were markedly increased from the level in the sham-operated rat bladder. Sectioning of hypogastric or both nerve pathways led to a less significant increase. It was therefore postulated that the majority of VIP-immunoreactive nerves originate from ganglia located either close to the bladder or within the bladder wall. It is interesting that in these experiments the VIP content of the bladder nerves is inversely related to the changes in motility that would be expected to result from the nerve sections.

Peptide immunoreactive nerves and cells of the guinea pig gall bladder and biliary pathways

Using the methods of immunocytochemistry and radioimmunoassay, five peptides (vasoactive intestinal polypeptide (VIP), substance P, somatostatin, met-enkephalin, and bombesin) have been found in the gall bladder and the biliary tracts of guinea pig and each of them possesses a characteristic distribution pattern. Networks of nerves containing each peptide were found in the smooth muscle, around blood vessels and, occasionally, in the lamina propria. The distribution of the peptide immunoreactive nerves in the gall bladder and biliary tract is similar to those found in the gut. Vasoactive intestinal polypeptide (11 +/- 1.5 pmol/g in the sphincters, mean +/- SEM) and substance P (21.5 +/- 1.8 pmol/g in the common bile duct) were found to be the most abundant peptides and a few VIP and substance P immunoreactive neurones were localised in the ganglionated plexus. Bombesin immunoreactive nerves were mainly seen in the sphincter of Oddi, where the mean concentration of extractable bombesin was 14.6 +/- 2 pmol/g. Somatostatin immunoreactive mucosal endocrine cells were identified in the epithelium of the common bile duct and the sphincter. The extractable somatostatin in these regions were 76 +/- 19 pmol/g and 162 +/- 30 pmol/g respectively.

Vasoactive intestinal polypeptide in the normal and unstable bladder

The possible involvement in idiopathic detrusor instability of a newly discovered type of autonomic nerve containing vasoactive intestinal polypeptide (VIP) has been studied. Immunocytochemistry and radioimmunoassay, using specific antibodies against VIP, were carried out on 20 biopsy specimens from the bladders of patients with detrusor instability and 20 specimens from control patients. The concentration of VIP in the unstable bladders was found to be markedly reduced from 36.52 +/- 4.8 pmol/g (mean +/- SEM) to 7.62 +/- 1.84 pmol/g (P less than 0.01). The number of VIP immunoreactive nerves was greatly decreased in all of the layers but particularly in the muscle layer of the unstable bladder in comparison with the controls. These findings may provide important information about the mechanism of this disorder.

Immunostaining of neuron-specific enolase as a diagnostic tool for Merkel cell tumors

Conventional histologic examination of Merkel cell tumors may result in misdiagnosis because of the close similarities these tumors bear to either malignant lymphomas or certain undifferentiated carcinomas. The authors have previously reported that neuron-specific enolase (NSE), a specific marker for neuroendocrine cells, is present in normal Merkel cells and can be used as a marker to identify this cell type. In this study, 11 Merkel cell tumors, identified employing electron microscopy, were studied using immunostaining of NSE by the peroxidase-antiperoxidase method. Varying intensities of NSE immunoreactivity were found in the cytoplasm of all the neoplastic cells in the different cases. The uniformly stained cytoplasm formed a small rim surrounding the large, unstained nucleus. Immunostaining of NSE thus provides a simple and reliable method for the differential diagnosis of Merkel cell tumors from other primary skin tumors which, with the exception of some malignant melanomas, have been shown not to contain NSE immunoreactivity.

Peptidergic innervation of the human male genital tract

Four peptides--vasoactive intestinal polypeptide, substance P, somatostatin and a peptide-like avian pancreatic polypeptide--have been found in nerves of the human male genitalia using highly sensitive and specific methods of immunocytochemistry and radioimmunoassay. Five other peptides (met-enkephalin, leu-enkephalin, neurotensin, bombesin and cholecystokinin-8) were absent. Vasoactive intestinal polypeptide was the most abundant peptide, its highest concentration being in the proximal corpus cavernosum. Immunoelectron microscopy localized this peptide to large (97 +/- 20 nm), round, electron-dense granules of p-type nerve terminals. Vasoactive intestinal polypeptide-immunoreactive neuronal cell bodies were found in the prostate gland and the root of the corpus cavernosum. Substance P immunoreactive material was present in smaller concentration and was mainly localized in nerves around the corpuscular receptors of the glans penis. Somatostatin immunoreactive nerves were associated mainly with the smooth muscle of the seminal vesicle and the vas deferens. When antiserum to avian pancreatic polypeptide was applied, certain nerves were stained, particularly in the vas deferens, the prostate gland and the seminal vesicle. However, chromatography detected no pure avian pancreatic polypeptide suggesting the presence of a structurally related substance, possibly neuropeptide Y, which cross-reacts with the avian pancreatic polypeptide antiserum. Similar distributions between vasoactive intestinal polypeptide-immunoreactive and acetylcholinesterase-positive nerves and between avian pancreatic polypeptide-immunoreactive and adrenergic nerves were observed. A general neuronal marker, neuron-specific enolase, was used to investigate the general pattern of the organ's innervation. The abundance and distribution patterns of these peptide-immunoreactive nerves indicate that they may play important roles in the male sexual physiology.

Distribution of bombesin, somatostatin, substance-P and vasoactive intestinal polypeptide in feline and porcine skin

The content and distribution of several regulatory peptides in the skin of cats and pigs, freshly obtained at surgery, have been investigated. Immunoreactive bombesin was evenly distributed at low concentrations in both species, being below the detection limit in the body and nose of the cat, and showing a peak value of 1.6 +/- 0.7 pmol/g in the tip of the pig's ear. Similar concentrations of somatostatin-immunoreactivity (-IR) were found but greater regional variation occurred in the pig with a low in the mid back of 0.4 +/- 0.1 and the highest value in the snout of 3.1 +/- 0.8. Substance-P-IR in the pig showed a marked variation in concentration, apparently parallelling skin sensitivity, with a low in the back of 0.4 +/- 0.7 and higher values around the anus (8.1 +/- 1.6), legs (6.8 +/- 1.8) and snout (13.5 +/- 3.6) whilst in the cat values ranged from 0.3 +/- 0.06 in the body to 5.0 +/- 0.9 in the front footpads. In contrast, vasoactive intestinal polypeptide (VIP)-IR showed greater variability in the cat, being below the assay's detection in the body and highest in the front and rear footpads (17 +/- 7 and 29 +/- 6 respectively), but in the pig most regions exhibited low concentrations with the exception of the snout which peaked at 12.0 +/- 5.0. Immunocytochemical localisation showed the peptides to be present in nerve fibres. Substance-P-IR was particularly localised in the snout of the pig just below the epithelium while VIP-IR was more concentrated in deeper layers, often associated with sweat glands and blood vessels.

Neuropeptide tyrosine (NPY)--a major cardiac neuropeptide

A newly discovered bioactive peptide, neuropeptide tyrosine (NPY), has been found in the human cardiac nervous system. Dense concentrations of NPY-immunoreactive nerve fibres were found in association with nodal tissue (atrioventricular node 22.1 +/- 3.7 pmol/g). NPY nerve fibres were seen in close contact with cardiac muscle fibres and were also found around the coronary vessels (19.6 +/- 6.2 pmol/g). Analysis of the peptide by high-performance liquid chromatography demonstrated that it was present in a single molecular form, closely similar or identical to that of the isolated bioactive peptide. Cardiac function in man has long been known to be influenced by cholinergic and adrenergic nerves. There now appears to be a further component of the nervous system in the human heart, involving peptidergic nerves containing NPY.

Repeated application of first-layer antiserum improves immunofluorescence staining: a modification of the indirect immunofluorescence staining procedure

Repeated application of the first-layer antiserum in the indirect immunofluorescence technique considerably improves the immunostaining. The modified method reveals more antigenic sites and increases the contrast between specific and background stainings, particularly where sparsely distributed antigenic areas are to be investigated. The effect of this novel immunostaining procedure is compared with that of the routine procedure and of other modifications. Possible mechanisms for the improving effect are discussed. A procedure of combined modifications is recommended for exploration of non-abundant antigens or for achieving a high-quality photograph.

Improved section adhesion for immunocytochemistry using high molecular weight polymers of L-lysine as a slide coating

Poly-L-lysine (PPL) has been used to coat glass slides in the preparation of tissue sections for immunocytochemical staining. The adhesive properties of different molecular weight (m.w.) polymers of L-lysine have been tested on pre-fixed cryostat sections which were subjected to a 3 day washing treatment. It has been found that the higher the molecular weight of the polymer, the greater the adhesive force it provides. PLL (m.w. 350,000) at concentrations in the range of 0.05-0.1% was found to be the most effective polymer.

The value of S-100 immunostaining as a diagnostic tool in human malignant melanomas. A comparative study using S-100 and neuron-specific enolase antibodies

The brain proteins S-100 and neuron-specific enolase have been reported by separate groups to be present in human malignant melanomas. There is no systematic study comparing the occurrence of these proteins in the same tumour specimens. We have examined 33 primary malignant melanomas, including 5 which were amelanotic, and 25 metastatic melanomas using immunohistochemical methods with specific, non-cross-reacting antibodies to S-100 and NSE. We found S-100 immunoreactivity to be present in all cases but one, whereas NSE immunoreaction was very weak and patchy, and present in only 6 cases. S-100 immunoreactivity was not demonstrated in 40 control tumours, either primary or metastatic in skin, including basal- and squamous-cell carcinomas, spindle-cell sarcomas, lymphomas and Merkel cell tumours. All intradermal (n = 4) and compound (n = 1) naevi were positive for S-100, 2 blue naevi showing much less reaction. NSE immunoreactivity was detected in Merkel cell tumours (n = 8), undifferentiated (n = 2) and small cell (n = 1) carcinomas, and all melanocytic naevi. It is suggested therefore that antibody to S-100 is the reagent of choice for demonstration of melanocytic tumours, and may be especially valuable in the diagnosis of amelanotic melanoma or metastatic tumours of doubtful origin where melanoma is suspected.

Immunogold staining procedure for the localisation of regulatory peptides

The use of protein A- and IgG-conjugated colloidal gold staining methods for the immuno-localisation of peptide hormones and neurotransmitters at light- and electron microscope level are described and discussed. Bright-field and dark-ground illumination modes have been used to visualise the gold-labelled antigenic sites at the light microscope level. Immunogold staining procedures at the ultrastructural level using region-specific antisera have been adopted to localise specific molecular forms of peptides including gastrin (G17 and G34), glucagon and pro-glucagon, insulin and pro-insulin, in normal tissue and in tumours of the gastroenteropancreatic system. Similar methods have been used to demonstrate the heterogeneity of p-type nerves in the enteric nervous system. Vasoactive intestinal polypeptide (VIP) has been localised to granular sites (mean +/- S.D. granule diameter = 98 +/- 19 nm) in nerve terminals of the enteric plexuses and in tumour cells of diarrhoeogenic VIP-producing neoplasias (mean +/- S.D. granule diameter = 126 +/- 37 nm) using immunogold procedures applied to ultraviolet-cured ultrathin sections. Co-localisation of amines and peptides in carotid body type I cells and in chromaffin cells of normal adrenal medulla and phaeochromocytomas has also been demonstrated. Advantages of the immunogold procedures over alternative immunocytochemical techniques are discussed.

Vipergic nerves in the penis

High concentrations of vasoactive intestinal polypeptide (VIP) were detected by immunocytochemistry and radioimmunoassay in thirty surgical specimens of male external genitalia. VIP was found exclusively in fine autonomic nerves. VIPergic nerves were most densely concentrated in the penis around the pudendal arteries and in the erectile tissue of the corpus cavernosum. Considerable numbers of VIP nerve fibres were also seen in the vas deferens and epididymis. VIP is known to exert regulatory actions on blood-flow, secretion, and muscle tone. Its presence in considerable amounts in the male genital tract suggests that this newly discovered peptide neurotransmitter may be important in the nervous control of male external genitalia.

Neuron-specific enolase in the Merkel cells of mammalian skin. The use of specific antibody as a simple and reliable histologic marker

Merkel cells are specialized skin receptor cells, characterized by their particular location in the epidermis and close association with nerve terminals. Although they can be distinguished ultrastructurally by their small, electron-dense secretory granules, there is no specific and reliable method for identifying them by light microscopy. Using antibodies to neuron-specific enolase (NSE), the authors have shown sparsely distributed groups of specifically immunostained cells and associated nerve terminals in the nose skin of cats and rats. These cells were easily distinguished from other epithelial cell types, including melanocytes and Langerhans cells and had all the morphologic features of Merkel cells and their so-called neurite complexes, including the characteristic cytoplasmic secretory granules (60 nm in diameter). NSE immunostaining is a simple and reliable method for the specific light-microscopic staining of Merkel cells and provides further evidence for NSE as a marker for the diffuse neuroendocrine system.