Calcitonin Gene-related Polypeptide Research Articles

Calcitonin Related Polypeptide Alpha Mediates Oral Cancer Pain.

Oral cancer patients suffer pain at the site of the cancer. Calcitonin gene related polypeptide (CGRP), a neuropeptide expressed by a subset of primary afferent neurons, promotes oral cancer growth. CGRP also mediates trigeminal pain (migraine) and neurogenic inflammation. The contribution of CGRP to oral cancer pain is investigated in the present study. The findings demonstrate that CGRP-immunoreactive (-ir) neurons and neurites innervate orthotopic oral cancer xenograft tumors in mice. Cancer increases anterograde transport of CGRP in axons innervating the tumor, supporting neurogenic secretion as the source of CGRP in the oral cancer microenvironment. CGRP antagonism reverses oral cancer nociception in preclinical oral cancer pain models. Single-cell RNA-sequencing is used to identify cell types in the cancer microenvironment expressing the CGRP receptor components, receptor activity modifying protein 1 Ramp1 and calcitonin receptor like receptor (CLR, encoded by Calcrl). Ramp1 and Calcrl transcripts are detected in cells expressing marker genes for Schwann cells, endothelial cells, fibroblasts and immune cells. Ramp1 and Calcrl transcripts are more frequently detected in cells expressing fibroblast and immune cell markers. This work identifies CGRP as mediator of oral cancer pain and suggests the antagonism of CGRP to alleviate oral cancer pain.

Genoset for CALCA and RAMP1 Single Nucleotide Polymorphisms Are Related to the Magnitude of Headache Symptoms After Concussion: A Preliminary Observation

Determine whether single nucleotide polymorphisms (SNPs) of the calcitonin gene-related polypeptide (CGRP)-alpha (CALCA) and the receptor activity modifying protein-1 (RAMP1) are related to headache burden during the first week after concussion. Post-traumatic headache is a commonly reported symptom after concussion. SNPs related to CGRP are involved in the pathogenesis of migraine headaches and contribute to pain transmission and neurogenic inflammation. It is unclear in concussed persons if the headache burden is associated with genetic variations related to CGRP. A prospective study was performed in 34 concussed athletes (gender: 23 female, 11 male; age: 20 ± 1 years; height: 1.75 ± 0.12 meters; weight: 73 ± 14 kilograms). Participants completed the symptom evaluation checklist from the SCAT3 within 48 hours of injury (V1), and 4 (V2) and 7 (V3) days after injury. For each visit, the self-reported score (0-6) for headache, pressure in head, blurred vision, and sensitivity to light/noise were summed. The area under-the-curve (AUC) was computed for the early (EHB: V1 to V2) and late (LHB: V2 to V3) burden of headache-related symptoms. A saliva sample was obtained and a commercial laboratory identified the genotype for CALCA (rs3781719) and RAMP1 (rs10185142) using PMR-array. RAMP1 genotypes RAMP1 (TT, TC, CC) and CALCA (AA, AG, GG) genotypes were dichotomized (T+, T-, and A+, A- respectively) and concatenated (T + A+, T + A-, T-A+, T-A-) for analyses. A significant difference for EHB (p = 0.003, partial η2 = 0.417) was present across RAMP1+CALCA genotypes, but not for the LHB. The T + A+ subgroup had a significantly elevated EHB compared to the all-other subgroups (p < 0.05: T + A + [n = 16]: 31.6 ± 2.6; T + A - [n = 9]: 17.7 ± 3.6; T-A+ [n = 8]: 18.4 ± 3.7; T-A-[n = 1]: 0.0 ± 0.0). Gender served as a covariate and diagnosed concussion history had no impact. The current analysis provides a proof-of-concept to suggest that the combined T + A+ genoset from RAMP1+CALCA are associated with a greater headache burden in the first 4 days after concussion injury.

Effects of co-administration of vitamin E and lithium chloride on chronic constriction injury-induced neuropathy in male Wistar rats: Focus on antioxidant and anti-inflammatory mechanisms.

This study investigated the antinociceptive effects of co-administration of lithium chloride (LiCl) and vitamin E (Vit E) on chronic constriction injury (CCI)-induced peripheral neuropathy in male Wistar rats. It further explored the anti-inflammatory and neuroprotective properties of LiCl and Vit E, which may be complementary to the antinociceptive effects of the two substances. Thirty-six male Wistar rats, 190.00±10.00g of body weight were randomly assigned to 6 experimental groups and administered with normal saline, Vit E, LiCl, or their combination, once daily for 21days. CCI was used to induce neuropathic pain (NP) and mechanical allodynia was assessed using von Frey filaments and pinprick test. Open field maze (OFM) was used to assess the exploratory behavior. Biochemical parameters were assessed in the dorsal root ganglion after 21days of treatment. Mechanical allodynia was developed in rats following CCI. Co-administration of LiCl and Vit E synergistically reduced mechanical hyperalgesia in rats which were significantly different compared with the single administration of either Vit E or LiCl. Combined doses of Vit E and LiCl significantly increases the explorative behavior in the OFM. CCI increased malondialdehyde (MDA), tumor necrotic factor-alpha (TNF-α), calcitonin gene-related polypeptide, calcium ion (Ca2+ ), and reduced superoxide dismutase (SOD) activities. Co-administration of LiCl and Vit E significantly reduced MDA, TNF-α, but increased SOD compared with ligated control. The findings revealed that the synergistic effects of the co-administration of Vit E and LiCl in ameliorating NP are mediated by their anti-inflammatory and antioxidant properties.

Single nucleotide polymorphisms for calcitonin gene-related polypeptide are related to the magnitude of headache symptoms after concussion: A preliminary observation (4525)

Single nucleotide polymorphisms for calcitonin gene-related polypeptide are related to the magnitude of headache symptoms after concussion: A preliminary observation (4525)

Magnesium-Based Whitlockite Bone Mineral Promotes Neural and Osteogenic Activities

Nerves spread throughout human bone minerals and play an important role in regulating osteogenic homeostasis. However, whether the distributive nerves can sense bone minerals and the role of bone minerals in nerve outgrowth are still unclear. We hypothesized that a natural magnesium-containing bone mineral, whitlockite (WH), the second most abundant bone mineral in the human body, could simultaneously promote both osteogenic and neural activities. To verify the hypothesis, both WH and hydroxyapatite (HAP) nanoparticles were synthesized, and their characterization was completed by Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The effect of WH on neural differentiation of mesenchymal stem cells (MSCs) and neural progenitor cells (NPCs) in 2D and 3D culture was examined by immunostaining and quantitative real-time polymerase chain reaction (qRT-PCR). The secretion of calcitonin gene-related polypeptide (CGRP) was examined by enzyme-linked immunosorbent assay (ELISA). The neural and osteogenic differentiation in a preosteoblasts and NPCs coculture system was examined by immunostaining and qRT-PCR. The results showed that WH promotes the gene and protein expression of neuronal specific marker (MAP-2 and βIII-tubulin) in 2D and 3D culture systems. In addition, the neurite length in the WH group was significantly longer than in other groups. Furthermore, both neural differentiation and osteogenic differentiation were simultaneously enhanced in the WH group in the coculture system. Thus, this study demonstrated the simultaneous stimulatory effect of WH bone mineral on neural and osteogenic activities, which provided WH as a valuable material for bone regeneration.

Immunohistochemical analysis of the mouse celiac ganglion: An integrative relay station of the peripheral nervous system

Celiac ganglia are important sites of signal integration and transduction. Their complex neurochemical anatomy has been studied extensively in guinea pigs but not in mice. The goal of this study was to provide detailed neurochemical characterization of mouse celiac ganglia and noradrenergic nerves in two target tissues, spleen and stomach. A vast majority of mouse celiac neurons express a noradrenergic phenotype, which includes tyrosine hydroxylase (TH), vesicular monoamine transporter 2, and the norepinephrine transporter. Over 80% of these neuron also express neuropeptide Y (NPY), and this coexpression is maintained by dissociated neurons in culture. Likewise, TH and NPY were colocalized in noradrenergic nerves throughout the spleen and in stomach blood vessels. Somatostatin was not detected in principal neurons but did occur in small, TH-negative cells presumed to be interneurons and in a few varicose nerve fibers. Cholinergic nerves provided the most abundant input to the ganglia, and small percentages of these also contained nitric oxide synthase or vasoactive intestinal polypeptide. A low-to-moderate density of nerves also stained separately for the latter markers. Additionally, nerve bundles and varicose nerve fibers containing the sensory neuropeptides, calcitonin gene-related polypeptide, and substance P, occurred at variable density throughout the ganglia. Collectively, these findings demonstrate that principal neurons of mouse celiac ganglia have less neurochemical diversity than reported for guinea pig and other species but receive input from nerves expressing an array of neurochemical markers. This profile suggests celiac neurons integrate input from many sources to influence target tissues by releasing primarily norepinephrine and NPY.

Determination of stable reference genes for RT-qPCR expression data in mechanistic pain studies on pig dorsal root ganglia and spinal cord

RNA expression levels for genes of interest must be normalised with appropriate reference or “housekeeping” genes that are stably expressed across samples and treatments. This study determined the most stable reference genes from a panel of 6 porcine candidate genes: beta actin (ACTB), beta-2-microglobulin (B2M), eukaryotic elongation factor 1 gamma-like protein (eEF-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), succinate dehydrogenase complex subunit A (SDHA), Ubiquitin C (UBC) in sacral dorsal root ganglia and spinal cord samples collected from 16 tail docked pigs (2/3rds of tail amputated) 1, 4, 8 and 16weeks after tail injury (4 pigs/time point). Total RNA from pooled samples was measured by SYBRgreen real-time quantitative PCR. Cycle threshold values were analysed using geNorm, BestKeeper and NormFinder PCR analysis software. Average expression stability and pairwise variation values were calculated for each candidate reference gene. GeNorm analysis identified the most stable genes for normalisation of gene expression data to be GAPDH>eEF-1>UBC>B2M>ACTB>SDHA for dorsal root ganglia and ACTB>SDHA>UBC>B2M>GAPDH>eEF-1 for spinal cord samples. Expression stability estimates were verified by BestKeeper and NormFinder analysis. Expression stability varied between genes within and between tissues. Validation of most stably expressed reference genes was performed by normalisation of calcitonin gene related polypeptide beta (CALCB). The results show similar patterns of CALCB expression when the best reference genes selected by all three programs were used. GAPDH, eEF-1 and UBC are suitable reference genes for porcine dorsal root ganglia samples, whereas ACTB, SDHA and UBC are more appropriate for spinal cord samples.

Application of the chronic constriction injury of the partial sciatic nerve model to assess acupuncture analgesia.

PurposeTo validate and explore the application of a rat model of chronic constriction injury to the partial sciatic nerve in investigation of acupuncture analgesia.MethodsChronic constriction injury of the sciatic nerve (CCI) and chronic constriction injury of the partial sciatic nerve (CCIp) models were generated by ligating either the sciatic nerve trunk or its branches in rats. Both models were evaluated via paw mechanical withdrawal latency (PMWL), paw mechanical withdrawal threshold (PMWT), nociceptive reflex-induced electromyogram (C-fiber reflex EMG), and dorsal root ganglion immunohistochemistry. Electroacupuncture (EA) was performed at GB30 to study the analgesic effects on neuropathic pain and the underlying mechanisms.ResultsFollowing ligation of the common peroneal and tibial nerves, CCIp rats exhibited hindlimb dysfunction, hind paw shrinkage and lameness, mirroring those of CCI rats (generated by ligating the sciatic nerve trunk). Compared to presurgery measurements, CCIp and CCI modeling significantly decreased the PMWL and PMWT. EA at GB30 increased the PMWL and PMWT in both CCI and CCIp rats. Calcitonin gene-related polypeptide and substance P expressions were apparently increased in both CCI and CCIp groups, but were not different from each other. The C-fiber reflex EMG of the biceps femoris was preserved in CCIp rats, but it could not be recorded in CCI rats on the 5th day after nerve ligation. The C-fiber reflex EMG was reduced at 0, 1, and 2 minutes after EA in CCIp rats, but only at 0 and 1 minute after EA in normal rats.ConclusionThe CCIp model is better than the CCI model for studying acupuncture analgesia on chronic neuropathic pain and the underlying mechanisms.

Distribution and sub-types of afferent fibre in the mouse urinary bladder

AimIncreased afferent fibre activity contributes to pathological conditions such as the overactive bladder syndrome. Nerve fibres running near the urothelium are considered to be afferent as no efferent system has yet been described. The aim of this study was to identify sub-types of afferent nerve fibres in the mouse bladder wall based on morphological criteria and analyse regional differences. Materials and methods27 bladders of six month old C57BL/6 mice were removed and tissues were processed for immunohistochemistry. Cryostat sections were cut and stained for Protein Gene Product 9.5 (PGP), calcitonin gene related polypeptide (CGRP), neurofilament (NF), vesicular acetylcholine transporter (VAChT) and neuronal nitric oxide synthase (nNOS). ResultsIn the sub-urothelium, different types of afferent nerve fibre were found, i.e. immunoreactive (IR) to; CGRP, NF, VAChT, and/or nNOS. At the bladder base, the sub-urothelium was more densely innervated by CGRP-IR and VAChT-IR nerve fibres, then at the lateral wall. NF- and nNOS nerves were sparsely distributed in the sub-urothelium throughout the bladder. At the lateral wall the inner muscle is densely innervated by CGRP-IR nerve fibres. NF, VAChT and nNOS nerves were evenly distributed in the different muscle layers throughout the bladder. Nerve fibre terminals expressing CGRP and NF were found within the extra-mural ganglia at the bladder base. ConclusionsDifferent types of afferent nerve fibres were identified in the sub-urothelium of the mouse bladder. At the bladder base the sub-urothelium is more densely innervated than the lateral wall by CGRP-IR and VAChT-IR afferent nerve fibres. CGRP and NF afferent nerve fibres in the muscle layer probably relay afferent input to external ganglia located near the bladder base. The identification of different afferent nerves in the sub-urothelium suggests a functional heterogeneity of the afferent nerve fibres in the urinary bladder.

A Transcriptome-Led Exploration of Molecular Mechanisms Regulating Somatostatin-Producing D-Cells in the Gastric Epithelium.

The stomach epithelium contains a myriad of enteroendocrine cells that modulate a range of physiological functions, including postprandial secretion of regulatory peptides, gastric motility, and nutrient absorption. Somatostatin (SST)-producing D-cells are present in the oxyntic and pyloric regions of the stomach, and provide a tonic inhibitory tone that regulates activity of neighboring enteroendocrine cells and gastric acid secretion. Cellular mechanisms underlying the effects of regulatory factors on gastric D-cells are poorly defined due to problems in identifying primary D-cells, and uncertainty remains about which stimuli influence D-cells directly. In this study, we introduce a transgenic mouse line, SST-Cre, which upon crossing with Cre reporter strains, facilitates the identification and purification of gastric D-cells, or cell-specific expression of genetically encoded calcium indicators. Populations of D-cells from the gastric antrum and corpus were isolated and analyzed by RNA sequencing and quantitative RT-PCR. The expression of hormones, hormone receptors, neurotransmitter receptors, and nutrient receptors was quantified. Pyy, Gipr, Chrm4, Calcrl, Taar1, and Casr were identified as genes that are highly enriched in D-cells compared with SST-negative cells. Hormone secretion assays performed in mixed gastric epithelial cultures confirmed that SST secretion is regulated by incretin hormones, cholecystokinin, acetylcholine, vasoactive intestinal polypeptide, calcitonin gene-related polypeptide, oligopetides, and trace amines. Cholecystokinin and oligopeptides elicited increases in intracellular calcium in single-cell imaging experiments performed using cultured D-cells. Our data provide the first transcriptomic analysis and functional characterization of gastric D-cells, and identify regulatory pathways that underlie the direct detection of stimuli by this cell type.

Interaction between Pirenzepine and Ninjinto, a Traditional Japanese Herbal Medicine, on the Plasma Gut-Regulated Peptide Levels in Humans

The Japanese herbal medicine (Kampo) Ninjinto has been used for the treatment of gastroenteritis, esogastritis, gastric atony, gastrectasis, vomiting, and anorexia. The pharmacological effects of Ninjinto on the gastrointestine are due to changes in the levels of gut-regulated peptide, such as motilin, somatostatin, calcitonin gene-related peptide (CGRP), substance P, and vasoactive intestinal polypeptide (VIP). The release of these peptides is controlled by acetylcholine (ACh) from the preganglionic fibers of the parasympathetic nerve. Thus, we examined the effects of the selective M1 muscarinic receptor antagonist pirenzepine on the elevation of Ninjinto-induced plasma the area under the plasma gut-regulated peptide concentration-time curve from 0 to 240 min (AUC0→240 min) in humans. Oral pretreatment with pirenzepine significantly reduced the Ninjinto-induced elevation of plasma motilin and substance P release (AUC0→240 min). Combined treatment with Ninjinto and pirenzepine significantly increased the release of plasma somatostatin (AUC0→240 min) compared with administration of Ninjinto alone or placebo. Ninjinto appeared to induce the release of substance P and motilin into plasma mainly through the activation of M1 muscarinic receptors, and pirenzepine may affect the pharmacologic action of Ninjinto by the elevation of plasma substance P, motilin, and somatostatin.

Secretin mRNA in the Subdivision of Primary Sensory Neurons in the Trigeminal Ganglion of Rats

The primary sensory neurons use glutamate as a major neurotransmitter. Several neuropeptides are also found in these neurons. In our laboratory we demonstrated secretin-like immunoreactivity in primary sensory neurons of several species including human, rat and cat. In the present experiment utilizing in situ hybridization, we have demonstrated for the first time that secretin is not only immunostained but is also expressed in the primary sensory neurons of the trigeminal ganglion of male rats. In intact rats, secretin mRNA was not observed; we had to use intracerebroventricular colchicine administration to induce the expression of secretin. Secretin was expressed in about 5% of the cells in all the three subdivisions of the trigeminal ganglion. The secretin-synthetizing cells were large and medium sized, and their mean diameter was about 50 μm. When we compared the percentage and the size of secretin to that of calcitonin gene-related peptide (CGRP), substance-P (SP) and vasoactive intestinal polypeptide (VIP) cells, it was found that CGRP, SP and VIP are present in about 15-20% of the cells and their mean diameter is about 20-25 μm. The morphometric data indicate that secretin is present in a subdivision of neurons that is different from the subdivision of the CGRP, SP and VIP cells. It is suggested that secretin may modulate the function of the primary neurotransmitter.

Modification of Innervation Pattern by Fluoroquinolone Treatment in the Rat Salivary Glands

Fluoroquinolone antibiotics (FQAs) are widely used in dental and medical therapy. Despite their known severe adverse actions on the central and peripheral nervous system, little attention has been directed toward the potential toxic side effects of these compounds on the oral tissues. As the saliva secretion is controlled by the nervous system and neuropeptides, the neurotoxic effect of pefloxacin (PEF), a representative member of FQAs, was studied in rats in the present work. Previously, we demonstrated a significant weight loss of parotid gland tissue, a marked decrease in 3H-thymidine incorporation, a decreased volume of saliva and amylase activity of the glandular tissue in response to PEF. Animals received intraperitoneal injection of PEF (20 mg/100 g body weight daily) for 3 and 7 days. Normal histology, and neurofilament 200, substance P (SP) and calcitonin gene-related polypeptide (CGRP) containing nerve fibers were detected with immunohistochemical methods. A marked decrease of the weights in salivary glands and the acinar diameters were measured. Similarly, a strong and significant decrease of the number of SP and CGRP containing nerve fibers were detected. These findings suggest that the impaired morphology and innervation pattern of salivary glands is related to the neurotoxic adverse effect of FQA treatment.

Role of Central Calcitonin Gene-Related Peptide (CGRP) in Locomotor and Anxiety- and Depression-Like Behaviors in Two Mouse Strains Exhibiting a CGRP-Dependent Difference in Thermal Pain Sensitivity

We have previously shown that, in AKR and C57BL/6 mice, a genetic polymorphism results in differential expression of the peptide, calcitonin gene-related polypeptide (CGRP), explaining a strain difference in thermal pain sensitivity. Although CGRP is widely distributed in the brain, little is known about the effects of supraspinal CGRP. We used AKR and C57BL/6 mice as a model to explore the effects of centrally (intracerebroventricular) injected CGRP and the CGRP receptor antagonists, CGRP(8-37) and BIBN4096BS, in a series of behavioral assays. Locomotor activity was significantly increased in C57BL/6 mice following the injection of BIBN4096BS and in both strains after the administration of CGRP(8-37) into the third ventricle. CGRP increased paw-withdrawal latencies in C57BL/6 mice only, while decreasing depression-like behaviors in both strains in the forced-swimming test. CGRP and CGRP receptor antagonists failed to modulate activity in the elevated plus maze, a model of anxiety. Taken together, these results suggest a complex role for supraspinal CGRP systems in the regulation of locomotion, nociception, and depression-like behaviors.

Neuropeptides and the Regulation of Islet Function

The pancreatic islets are richly innervated by autonomic nerves. The islet parasympathetic nerves emanate from intrapancreatic ganglia, which are controlled by preganglionic vagal nerves. The islet sympathetic nerves are postganglionic with the nerve cell bodies located in ganglia outside the pancreas. The sensory nerves originate from dorsal root ganglia near the spinal cord. Inside the islets, nerve terminals run close to the endocrine cells. In addition to the classic neurotransmitters acetylcholine and norepinephrine, several neuropeptides exist in the islet nerve terminals. These neuropeptides are vasoactive intestinal polypeptide, pituitary adenylate cyclase–activating polypeptide, gastrin-releasing polypeptide, and cocaine- and amphetamine-regulated transcript in parasympathetic nerves; neuropeptide Y and galanin in the sympathetic nerves; and calcitonin gene–related polypeptide in sensory nerves. Activation of the parasympathetic nerves and administration of their neurotransmitters stimulate insulin and glucagon secretion, whereas activation of the sympathetic nerves and administration of their neurotransmitters inhibit insulin but stimulate glucagon secretion. The autonomic nerves contribute to the cephalic phase of insulin secretion, to glucagon secretion during hypoglycemia, to pancreatic polypeptide secretion, and to the inhibition of insulin secretion, which is seen during stress. In rodent models of diabetes, the number of islet autonomic nerves is upregulated. This review focuses on neural regulation of islet function, with emphasis on the neuropeptides.

Location of interstitial cells and neurotransmitters in the mouse bladder

To investigate whether interstitial cells (ICs) are present in the adult mouse bladder, and what transmitters characterize adjacent nerve fibres, as ICs in human and guinea-pig bladder lie close to nerve fibres but transmitters present in these nerves have not yet been reported. Sections of the bladder wall from 12 adult male mice (six each, aged 3-4 or 18-24 months) were incubated in carboxygenated Krebs' solution containing isobutyl-methyl-xanthene (1 mm), followed by the nitric oxide (NO) donor diethylamino-NONOate; control tissues remained in Krebs' solution. Samples were fixed in 4% paraformaldehyde and processed for immunofluorescence histochemistry for cGMP, neuronal NO synthase (nNOS), vesicular acetylcholine transferase (VAChT), calcitonin gene-related polypeptide (CGRP) and protein gene product (PGP) 9.5. ICs were identified as non-neuronal cells of appropriate morphology manifesting an increase in cGMP after exposure to the NO donor. ICs were apparent in the outer muscle, but not the inner muscle or suburothelial region. nNOS- and CGRP-immunoreactive fibres were close to and alongside IC processes. In contrast, nerve fibres containing VAChT were only occasionally found close to ICs and rarely running alongside them. ICs showed no immunoreactivity to c-kit. There was no overt difference in IC cell distribution between young and aged adult specimens. Older mice showed patchy denervation of the detrusor, but ICs were not specifically affected. ICs are confined to the outer part of the bladder wall in the mouse and may receive peptidergic and nitrergic innervation, which might serve to modulate their putative functional role. Alterations in the overall IC population do not appear to underlie ageing-related changes in lower urinary tract function.

Changes in vasoconstrictor and vasodilator neurotransmitters in nerves supplying arterioles in developing colorectal polyps

To examine the changes that occur in the immunohistochemistry of vasoconstrictor and vasodilator transmitters in nerves supplying early and advanced colorectal polyps. We studied the perivascular innervation of submucosal arterioles of colorectal polyps (n = 18) and the innervation of the epithelial layer of polyps compared to normal controls (n=8), using immunohistochemical markers for the neurotransmitters; noradrenaline (NA) (marker used; tyrosine hydroxylase (TH)), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), substance P (SP), and calcitonin gene-related polypeptide (CGRP). (Advanced polyps; villous adenomas>1.5 cm, polyps with severe dysplasia or partial carcinoma). In submucosal arterioles there was a progressive decrease from controls through early polyps to advanced polyps in TH and NPY perivascular immunoreactivity (P<0.015 for both). VIP and SP immunoreactivity was higher in early polyps compared to controls, but markedly reduced in advanced polyps (P<0.05 for VIP). Sparse CGRP immunoreactivity was present in polyps only. Neural VIP and SP immunoreactivity in the lamina propria of polyp mucosa was more intense than in controls. There is a decrease in vasoconstrictor neurotransmitters NPY and NA (shown by TH) around submucosal arterioles of both early and advanced polyps, but an increase in the vasodilator neurotransmitters, particularly VIP, in early colorectal polyps. These results suggest a predominantly vasodilatory neural influence in early polyps, perhaps indicating a mechanism that maintains polyp growth.

Neuroendocrine Carcinoma in the Nasal Cavity of Ten Dogs

Neuroendocrine (NE) carcinoma was diagnosed in 10 dogs. In six cases examined by cephalometric radiography and computerized tomography, a large mass was seen to fill the nasal cavity. Histopathologically, sheets, nests or ribbons of neoplastic cells were separated by delicate or thick fibrovascular stroma. The neoplastic cells were round, oval, or spindle-shaped; cytoplasmic granules and hyperchromatic nuclei with prominent nucleoli were present. Neoplastic cells were invariably immunohistochemically positive for cytokeratin (CK) AE1/AE3, neuron-specific enolase, chromogranin A and vasoactive intestinal polypeptide. Eight dogs were positive for S100 protein, seven for synaptophysin, five for protein gene product 9.5, two for somatostatin, and one for Leu-7. Immunolabelling gave negative results for CK 8, CK 19, calcitonin, calcitonin gene-related polypeptide, neurofilaments, serotonin, gastrin and glial fibrillary acidic protein. Ultrastructurally, the neoplastic cells contained a large number of round, membrane-bounded, densely-cored granules corresponding to neurosecretory granules. These observations were consistent with the neuroendocrine nature of the carcinomas.

Modification of the rat aortic wall during ageing; possible relation with decrease of peptidergic innervation.

Structural changes of the male rat aorta were followed from birth to old age in male and female rats. In males, the vessel media width and area progressively increase concomitantly with a decrease of nuclei density during ageing, suggesting an hypertrophy of the smooth muscle cells. These correlations were however not evidenced in females. TUNEL-positive cells were found in media of 4 and 6 months in both sexes, mainly on the luminal side and in the adventitia. When biochemical markers were investigated with immunohistochemistry, media was uniformly stained by the anti-vimentin and anti-alpha-smooth actin at all stages investigated. On the contrary, the surface of media stained with anti-desmin decreased during ageing, especially on the luminal side. As observed with electron microscopy, with ageing the endothelium is replaced by small cells with pseudopodia adhering to the vestigial elastic lamina and infiltrating into the extracellular matrix left after the disappearance of smooth muscle cells. In addition, in the older rats (25-29 months) the elastic laminae are completely disorganised. Hypertrophy of the smooth muscle cells was confirmed by this approach. In parallel to this study, perivascular peptidergic innervation was stained with antibodies against calcitonin gene-related peptide (CGRP), substance P (SP), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) at different ages during the whole life of rats. These peptides are present in stages younger than 6 months, then gradually disappear. In one year animals and older, the peptidergic innervation has totally disappeared. We discuss the possible role of peptidergic innervation in the control of the vessel wall cellular stability during ageing.

Primary sensory neuron survival following targeted administration of nerve growth factor to an injured nerve.

Nerve injuries induce neurochemical changes within primary sensory neurons, including expression of neuropeptides, and a loss of a substantial proportion of the neurons may possibly be caused by a lack of neurotrophic support. In the present study the role of nerve growth factor (NGF) in preventing these changes was investigated in monkeys by giving NGF peripherally through a fibronectin (Fn) conduit. A sensory nerve (superficial radial) was transected and a gap of 5 mm was bridged with either autologous sural nerve graft (SNG), Fn, or Fn impregnated with NGF (Fn-NGF). After four months the dorsal root ganglia, that received the cutaneous afferents of the nerve, were removed and analysed by quantitative immunohistochemistry using antibodies to calcitonin gene related polypeptide (CGRP) and substance P. The percentage of immunostained cells was taken as an indication of neuronal survival. The results showed that SNG and Fn-NGF reduced the loss of CGRP positive sensory neurons compared with Fn alone. For substance P-positive neurons the differences were small with only a tendency towards reduction of neuronal death after NGF had been given, suggesting that NGF might act preferentially on a subpopulation of CGRP immunoreactive sensory neurons that do not coexist with substance P.