Immunoreactive Nerve Research Articles

Cellular localization and distribution of dopamine D 4 receptors in the rat cerebral cortex and their relationship with the cortical dopaminergic and noradrenergic nerve terminal networks

The role of the dopamine D 4 receptor in cognitive processes and its association with several neuropsychiatric disorders have been related to its preferential localization in the cerebral cortex. In the present work we have studied in detail the regional and cellular localization of the dopamine D 4 receptor immunoreactivity (IR) in the rat cerebral cortex and its relationship to the dopaminergic and noradrenergic nerve terminal networks, since both dopamine and noradrenaline have a high affinity for this receptor. High levels of D 4 IR were found in motor, somatosensory, visual, auditory, temporal association, cingulate, retrosplenial and granular insular cortices, whereas agranular insular, piriform, perirhinal and entorhinal cortices showed low levels. D 4 IR was present in both pyramidal and non-pyramidal like neurons, with the receptor being mainly concentrated to layers II/III. Layer I was observed to be exclusively enriched in D 4 IR branches of apical dendrites. Finally, mismatches were observed between D 4 IR and tyrosine hydroxylase and dopamine β-hydroxylase IR nerve terminal plexuses, indicating that these receptors may be activated at least in part by dopamine and noradrenaline operating as volume transmission signals. The present findings support a major role of the dopamine D 4 receptor in mediating the transmission of cortical dopamine and noradrenaline nerve terminal plexuses.

Stress protects from allergic sensitisation via Substance‐P modified antigen presentation

Stress is a potent immunomodulator and aggravator of atopic disease. In a combined murine model of atopic like‐allergic dermatitis (AD) and perceived stress (noise) we previously demonstrated that stress increases Substance P (SP) immunoreactive nerve fiber number and subsequent neurogenic inflammation. Stress also induced an altered Th1/Th2 cytokine balance indicating modulation of antigen presentation. To investigate the effect of stress and SP on dendritic cell‐T cell interaction during allergen sensitisation and the subsequent modification of allergic inflammation, we exposed AD mice to stress prior to sensitisation. Stress markedly increased dendritic cell (DC) migration and maturation in a SP dependent manner. Moreover, the effects of stress were selectively abolished when animals were treated with NK1 antagonist. Interestingly, in stressed AD mice, the number of regulatory CD4+CD25+ T cells (Tregs) was increased, while other T cell subsets were decreased. When dendritic cells from stressed AD mice were co‐cultured with T lymphocytes we measured higher medium concentrations of TH1 (IFN? and TNF?) vs. TH2 (IL‐4 and IL‐5) cytokines, as well as higher levels of IL‐2 indicating promotion of ‘anti‐allergic’ TH1 and T regulatory phenotypes. Concordantly with the stress and SP dependent alterations in DC‐T cell interaction disease severity (eosinophilic infiltrates, epidermal thickening) was significantly decreased. This reduction in skin inflammation was abrogated in mice treated with NK1 antagonist. Taken together, our data show that via SP‐dependent mechanisms stress may be involved in the sensitisation of atopic individuals to allergen and thereby determine the course of the disease.

An immunohistochemical study of endocrine cells in the iodoacetamine-induced rat's gastritis

The gastric epithelium is a complex stucture formed by tubular gastric glands. The gastric glands contain a wide variety of cell types according to the secretion of hydrochloric acid, proteases, mucus, pepsinogen and hormones. Endocrine and local paracrine mediators are of crucial importance for maintaining structural and functional integrity of the epithelium. Therefore our aim was to investigate the precise localization and density of the endocrine cells and their contacts in iodoacetamine-induced rat's gastritis. Methods: somatostatin (SOM), calcitonin gene-related peptide CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and galanin immunoreactive (IR) endocrine cells and nerve elements were detected by ABC immunohistochemistry. Results: The quantitative analysis of the density of the different neuropeptide containing endocrine cells and nerve fibres showed that the (IR) nerve fibres were found with different density. The number of SOM and CGRP IR endocrine cells increased significantly in the gastritis. Both endocrine cells possessed long cytoplasmic extensions and no cell-to-cell contact between parietal and endocrine cells was found. The number of SP, VIP, NPY IR nerve fibres also increased significantly in the gastritis, however, the others showed no alteration. The number of the immunocompetent cells was also increased (being lymphocytes, plasma cells and mast cells) and 16,8% of the immunocytes were IR for SP and 9, 4% of them were IR for NPY. In several cases close contacts were detected between IR nerve fibres and the immunocytes. Conclusions: The increased number of SOM and CGRP endocrine cells and SP IR nerve fibres might play a crucial role in the regulation of gastric acid secretion, including gastric ulcer disease and autoimmune gastritis. The main inhibitor of acid secretion is somatostatin. CGRP activates the mucin biosynthesis, both SOM and CGRP have a preventive action on gastric mucosal injury. The changes in the density of nerve fibres and immunocytes might be the consequences of the inflammation.

Expression of neuropeptide Y and its receptors in the cardinal ligaments and uterosacral ligaments in patients with pelvic organ prolapse

To evaluate the distribution of neuropeptide Y and its receptors in the cardinal ligament and uterosacral ligaments in women with and without pelvic organ prolapse (POP). Sixteen patients with pelvic organ prolapse entered the study. All patients were evaluated by pelvic organ prolapse quantitation (POP-Q). Group A consisted of six patients with grade I , II POP, and group B comprised ten patients with grade III, IV POP. Eight nonfunctional ovarian tumor patients without POP were recruited as control subjects. Biopsies of cardinal ligament and uterosacral ligament were obtained from each woman during surgery. Immunohistochemical study with polyclonal antibody against a general nerve marker S-100 and neuropeptide Y was performed on paraffin-embedded sections of all the samples. In addition, mRNA levels of the human NPY-Y1 and NPY-Y2 receptors were assessed in both patients and controls. (1) NPY immunoreactivities were identified in both cardinal ligament and uterosacral ligament NPY immunoreactive nerve fibers were insignificantly lower in POP patients (P > 0.05). The distribution pattern of NPY was similar in cardinal ligament and uterosacral ligament (P > 0.05). (2) mRNAs encoding the NPY-Y1 and NPY-Y2 receptors were detected in the pelvic supporting tissues. Besides the expected NPY-Y1 PCR products, an additional 97 bp long amplicon originating from an alternative splicing event was found in most tissues studied. (3) In cardinal ligaments, mRNA encoding NPY-Y1 receptor had a significant difference between group A (3.9 +/- 1.0) and B (6.0 +/- 1.5), and between control (3.4 +/- 0.9) and group B (P = 0.019, P = 0.004), while there was no significant difference between group A and controls (P = 0.082). In uterosacral ligaments, mRNA encoding NPY-Y1 receptor had no significant difference between Group A (6.0 +/- 1.1) and B (6.3 +/- 0.7), or between group A and controls (4.8 +/- 0.7; P = 0.151, P = 0.690); while there was a significant difference between group B and controls (P = 0.016). (4) mRNA encoding NPY-Y2 receptor had no significant difference between controls (0.49 +/- 0.34, 0.61 +/- 0.15), group A (0.56 +/- 0.21, 0.67 +/- 0.13) and group B (0.85 +/- 0.43, 0.69 +/- 0.21) patients in cardinal ligament and uterosacral ligaments (P > 0.05). (5) mRNA encoding NPY-Y1 (P = 0.084) and NPY-Y2 (P = 0.470) receptors had no significant difference between cardinal ligament and uterosacral ligament. There are NPY and NPY receptors in cardinal and uterosacral ligaments. The increased expression of NPY Y1 receptor may be related to local blood flow reduction and structural changes of pelvic supporting tissue.

Novel neurotransmitters of the human intrinsic cardiac nervous system

This study was done to anatomically identify novel neurotransmitters localized to human intrinsic cardiac ganglia (ICG). Samples were collected from 8 patients during cardiothoracic surgery and processed for immunofluorescent detection of specific neuronal markers. Colocalization of markers was evaluated by confocal microscopy. All intrinsic cardiac neuronal somata showed immunoreactivity for the cholinergic marker choline acetyltransferase (ChAT). These somata were bordered by cholinergic varicosities, evident as punctate immunostaining for high affinity choline transporter. Moderate to intense staining for neuronal nitric oxide synthase (nNOS) was likewise associated with all ganglion neurons as well as some proximal axons and nerve fiber bundles connected to ICG. Many calcitonin gene‐related peptide (CGRP)‐immunoreactive nerve fibers were identified in ICG, often surrounding cholinergic/nitrergic neuronal somata. Fewer nerve fibers displayed substance P (SP)‐immunoreactivity, but all SP was colocalized with CGRP. These findings suggest that NO may play a prominent role in cholinergic transmission within the human heart, CGRP being another key neuromodulator in the human intrinsic cardiac nervous system. Identification of such novel mediators may lead to new paradigms for cardiac neuromodulation. Supported by the AHA SE Affiliate and the Canadian Institutes for Health Research.

Distribution of ghrelin-like immunoreactive cells in amphioxus, Branchiostoma belcheri – A study of immunohistochemistry

The distribution of ghrelin-like immunoreactive cells in amphioxus ( Branchiostoma belcheri) was investigated by using immunohistochemical staining with rabbit antiserum against synthetical mammalian ghrelin. The results showed that ghrelin-like immunoreactive cells were distributed widely in the nervous system, Hatschek’s pit, wheel organ, digestive tract and gonads (ovary and testis). In nervous system, ghrelin-like immunoreactive neurons and their protrusions were distributed specifically on the dorsal side, ventral side and funnel part of brain vesicle, with a few dispersive immunoreactive nerve cells and their fibers in nerve tube. Ghrelin-like immunoreactivities were also detected in Hatschek’s pit epithelial cells and wheel organ cells, with positive substance located along cell membrane. In digestive tract, ghrelin-like immunoreactive cells existed in hepatic diverticulum, anterior and posterior region of midgut, and could be classified into two types, closed- and opened-type endocrine cells. The number of positive cells was most in hepatic diverticulum, secondary in posterior region of midgut and least in anterior region of midgut. In gonads, ghrelin-like immunoreactive substance was detected in oogonia, oocytes and follicle cells in ovary at the small and large growth stages and in early spermatogenic cells and Sertoli cells in testis. The extensive distribution of ghrelin-like cells in amphioxus suggested that these kinds of cells are conservative in evolution and diversified in function. At the same time, we found for the first time that ghrelin-like immunoreactive cells existed in brain vesicle and Hatschek’s pit, which provided new morphological evidence for the existence of an activation pathway between brain vesicle and Hatschek’s pit for the regulation of growth hormone excretion.

Substance P Stimulates Production of Interleukin 1 β and Tumor Necrosis Factor α in Fibroblasts From Hip Periprosthetic Membrane

Aseptic loosening remains the primary cause of failure in total joint arthroplasty. Substance P (SP)–immunoreactive nerve fibers have been detected in the pseudomembrane and pseudocapsular tissues of aseptic loose hip prostheses, suggesting that SP might be involved in the process of aseptic loosening. We isolated fibroblasts from periprosthetic membrane at the time of revision hip arthroplasty performed because of aseptic loosening. Fibroblasts were incubated in the presence of various concentrations of SP, and the levels of interleukin 1 β, and tumor necrosis factor α in the media were determined using enzyme-linked immunosorbent assay kit. We found that the levels of interleukin 1 β and tumor necrosis factor α increased in a time- and concentration-dependent manner. Our results suggested that SP might be involved in the pathogenesis of aseptic loosening.

Influence of liquid diet feeding on calcitonin gene-related peptide-like immunoreactive nerve fibers in rat temporomandibular joints during growth period

Biomechanical factors of masticatory functions are related to the development of the temporomandibular joint (TMJ) components during growth. However, the effects on nerve fibers have not been fully clarified. We investigated the influence of masticatory muscle activity on nerve fibers in the TMJ during growth by changing the consistency of diet. Twenty 3-week-old male Wistar rats were divided into two groups. The experimental group was fed a liquid diet, while the control group had a normal hard diet. Rats were sacrificed at 6-, and 9-week-old. We investigated the expression of calcitonin gene-related peptide-like immunoreactive (CGRP-LI) nerve fibers, which are most abundant in the TMJ and have a nociceptive function, using immunohistochemistry for CGRP. No significant difference in the number of CGRP-LI nerve fibers was detected in 6-week-old rats, but in 9-week-old ones the number in the experimental group was significantly greater than that in the control. We concluded that masticatory muscle activity in the TMJ closely correlates with peripheral sensory nerve fibers during growth.

Nociceptive Nerve Fibers in the Sacroiliac Joint in Humans

A positive response to sacroiliac joint intra-articular infiltration with local anesthetics is used to confirm sacroiliac joint pain. However, current anatomical and histological knowledge concerning the anatomy of pain perception within the sacroiliac joint intra- and peri-articular structures is insufficient to explain the efficacy of this infiltration, because of the use of unspecific histochemical visualization techniques. In this study, immunohistochemistry for calcitonin gene-related peptide (CGRP) and substance P was used to trace nociceptive fibers and receptors in the anterior and interosseous sacroiliac ligaments obtained from 5 human cadavers without history of sacroiliac joint pain. Microscopic analysis of stained slides showed presence of CGRP and substance P immunoreactive fibers. Thick, wavy, formed bundles were observed in dense and loose connective tissue, whereas single, beaded nerve fibers, occasionally ramified, were observed more frequently in the dense connective tissue and next to blood vessels. Based on their morphologic features, these immunoreactive structures were classified as receptors type IV. Additionally, receptors type II were found in anterior and interosseous ligaments, which contained CGRP or substance P immunoreactive free nerve endings. We conclude that the presence of CGRP and substance P immunoreactive fibers in the normal anterior capsular ligament and interosseous ligament provides a morphological and physiological base for pain signals originating from these ligaments. Therefore, diagnostic infiltration techniques for sacroiliac joint pain should consider extra- as well as intra-articular approaches.

Role of the amygdaloid cholecystokinin (CCK)/gastrin‐2 receptors and terminal networks in the modulation of anxiety in the rat. Effects of CCK‐4 and CCK‐8S on anxiety‐like behaviour and [3H]GABA release

The amygdala plays a key role in fear and anxiety. The intercalated islands are clusters of glutamate-responsive GABAergic neurons rich in cholecystokinin (CCK)-2 receptors which control the trafficking of nerve impulses from the cerebral cortex to the central nucleus of amygdala. In this study, the nature of the CCK-glutamate-GABA interactions within the rat rostral amygdala, and their relevance for anxiety, were studied. CCK/gastrin-like immunoreactive nerve terminals were found to be mainly restricted to the paracapsular intercalated islands and the rostrolateral part of the main intercalated island. Behaviourally, the bilateral microinjection of CCK-4 (0.043-4.3 pmol/side) or CCK-8S (4.3 pmol/side) into the rostrolateral amygdala reduced the open-arm exploration in the elevated plus-maze without affecting locomotion. In contrast, neither CCK-4 nor CCK-8S (0.043-4.3 pmol/side) had any effects in the shock-probe burying test as compared with their saline-treated controls. Biochemically, CCK-4 (0.3 and 1.5 microm), unlike CCK-8S, enhanced significantly the K(+)-stimulated release of [(3)H]GABA from amygdala slices. These effects were fully prevented by prior superfusion of the slices with either the selective CCK-2 receptor antagonist CR2945 (3 microm), or 6,7-dinitroquinoxaline-2,3(1H,4H)-dione (DNQX), 10 microm, a glutamatergic (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptor antagonist. It is suggested that CCK modulates glutamate-GABA mechanisms by acting on CCK-2 receptors via volume transmission occurring at the level of the basolateral amygdaloid nucleus and/or by synaptic or perisynaptic volume transmission in the region of the rostrolateral main and paracapsular intercalated islands, resulting in subsequent disinhibition of the central amygdaloid nucleus and anxiety or panic-like behaviour.

A new concept in orthodontics: faster and healthier tooth movement by regularly consuming xyilitol chewing gum

Xylitol was first discovered in the 19th century, it wasn’t until the 1960’s that commercial production was first implemented. Recent studies showed that xylitol chewing gum is beneficial for preventing caries and periodontal disease. Therefore, it is also advantageous for orthodontic treatment, especially the fixed orthodontics patients who have difficulties in acquiring optimal oral health, particularly periodontal health which important in remodeling. However, how consuming xylitol chewing gum may stimulate tooth movement and preventing root resorption is still unclear. It is suggested that chewing activities may stimulate tooth movement, since jaw hypofunction leads to lower mineral apposition and bone function; and narrow periodontal ligament (PDL). These conditions may lead to impaired remodeling process, and increases the susceptibility of root resorption during orthodontic tooth movement. Moreover, since stimulation of the PDL could be mechanoreceptive (i.e. chewing action) or nociceptive (i.e. painful stimulation), periodontal nerve fibers are supposed to play an important role in bone remodeling. It is supported by a study which revealed that during tooth movement, the galanin-containing immunoreactive nerve fibers, a part of primary sensory neurons in the PDL is increasing. Galanin is able to induce osteoclast differentiation that needed for bone resorption in orthodontic treatment. The objective of this study is to elucidate a new concept in using xylitol chewing gum as an excellent media to have a faster and healthier orthodontic movement. Since continuous chewing stimulates the PDL which enhances tooth movement, improves oral health, and prevents root resorption; it is concluded that this concept is possible.

The development of avian enteric nervous system: Distribution of artemin immunoreactivity

Among the factors that control neural crest cell precursors within the enteric nervous system, the ligands of the glial cell line-derived neurotrophic factor family (GFL) seem to be the most influential. Artemin, a member of the GFLs, was previously described only in the oesophagus and stomach of mouse embryos. In this study, the presence and distribution of artemin is reported in duck embryos and adults. Artemin immunoreactivity was apparent in the intestinal tract at embryonic day 7 (d7), firstly in the myenteric plexus and then in the submucous plexus. Later, artemin immunoreactive nerve fibres were also seen in the longitudinal muscle plexus, the circular muscle plexus, the plexus of the muscularis mucosa and in the mucosal plexus. Furthermore, at d7, weak labeling of artemin was detected in neurons and glial cells in the oesophagus, gastric region and duodenum. Subsequently, artemin was also detected in all other intestinal segments. Moreover, during development of the gut in the domestic duck, artemin immunoreactivity decreased in neuronal cell bodies, whilst it increased in neuronal fibres and glial cells. These findings suggest an involvement of artemin in the development and biology of the gut of the domestic duck.

Maternal Perinatal Undernutrition Drastically Reduces Postnatal Leptin Surge and Affects the Development of Arcuate Nucleus Proopiomelanocortin Neurons in Neonatal Male Rat Pups

A growing body of evidence suggests that maternal undernutrition sensitizes the offspring to the development of energy balance metabolic disorders such as type 2 diabetes, dyslipidemia, and obesity. The present study aimed at examining the impact of maternal undernutrition on leptin plasma levels in newborn male rats and on the arcuate nucleus proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons that are major leptin targets. Using a model of perinatal maternal 50% food-restricted diet (FR50) in the rat, we evaluated leptin plasma levels and hypothalamic POMC and NPY gene expression from postnatal day (PND) 4 to PND30 in both control and FR50 offspring. In control rats, a postnatal peak of plasma leptin was observed between PND4 and PND14 that reached a maximal value at PND10 (5.17 +/- 0.53 ng/ml), whereas it was dramatically reduced in FR50 pups with the higher concentration at PND7 (0.93 +/- 0.23 ng/ml). In FR50 animals, using semiquantitative RT-PCR and in situ hybridization, we showed that the hypothalamic POMC mRNA level was decreased from PND14 until PND30, whereas NPY gene expression was not significantly modified. In PND21 FR50 animals, we observed strikingly reduced immunoreactive beta-endorphin nerve fibers projecting to the hypothalamic paraventricular nucleus without affecting NPY projections. Our data showed that maternal undernutrition drastically reduces the postnatal surge of plasma leptin, disturbing particularly the hypothalamic wiring as well as the gene expression of the anorexigenic POMC neurons in male rat pups. These alterations might contribute to the adult metabolic disorders resulting from perinatal growth retardation.

Nerve Regeneration after Radiofrequency Application

Background Many patients with chronic tendinosis have experienced early pain relief after application of bipolar radiofrequency treatment. It is hypothesized that the mechanism of action may be the acute degeneration and/or ablation of sensory nerve fibers. Hypothesis After ablation or degeneration by bipolar radiofrequency, nerve fibers will have the ability to regenerate with time. Study Design Controlled laboratory study. Methods Eighteen Sprague-Dawley rats were used in this study. These rats were divided into 3 groups (30, 60, and 90 days after bipolar radiofrequency). These rats were treated with 2 points of bipolar radiofrequency applications to the left hindpaws with the Topaz microdebrider device. Right hindpaws were used as the contralateral control. Tissues were processed for neural class III β-tubulin or calcitonin gene-related peptide immunohistochemistry by using the free-floating avidin biotin complex technique. The numbers of neural class III β-tubulin—immunoreactive and calcitonin gene-related peptide-immunoreactive nerve fibers in the epidermis were counted and compared with those in the contralateral control. Results Although the numbers of nerve fibers demonstrated by both the antibodies of neural class III β-tubulin and calcitonin gene-related peptide were significantly decreased (P < .0001) until 60 days after bipolar radiofrequency treatment, regeneration of the epidermal nerve fibers occurred 90 days after treatment. Conclusion Bipolar radiofrequency treatment induced degeneration of sensory nerve fibers immediately after treatment, but by 90 days posttreatment, there was evidence of complete regeneration. Clinical Relevance Early degeneration followed by later regeneration of nerve fibers after bipolar radiofrequency treatment may explain long-term postoperative pain relief after microtenotomy for tendinosis.

Distribution and Function of the Hydrogen Sulfide–Sensitive TRPA1 Ion Channel in Rat Urinary Bladder

ObjectivesTo investigate the distribution of the transient receptor potential (TRP) A1 ion channel in the rat urinary bladder, and to study the effects of hydrogen sulfide (H2S) and known TRPA1 activators on micturition in conscious rats and on heterologously expressed ion channels. MethodsThe expression of TRPA1 in urinary bladder was studied with fluorescence immunohistochemistry and real-time PCR in female Sprague-Dawley rats. Cystometric investigations were performed in conscious animals subjected to intravesical administration of sodium hydrogen sulfide (NaHS, donor of H2S), allyl isothiocyanate (AI), and cinnamaldehyde (CA). Fluorometric calcium imaging was used to study the effect of NaHS on human and mouse TRPA1 expressed in CHO cells. ResultsTRPA1 immunoreactivity was found on unmyelinated nerve fibres within the urothelium, suburothelial space, and muscle layer as well as around blood vessels throughout the bladder. All TRPA1 immunoreactive nerves fibres also expressed TRPV1 immunoreactivity and vice versa. TRPA1 was also detected in urothelial cells at both transcriptional and protein levels. AI increased micturition frequency and reduced voiding volume. CA and NaHS produced similar changes in urodynamic parameters after disruption of the urothelial barrier with protamine sulfate. NaHS also induced calcium responses in TRPA1-expressing CHO cells, but not in untransfected cells. ConclusionsThe expression of TRPA1 on C-fibre bladder afferents and urothelial cells together with the finding that intravesical TRPA1 activators initiate detrusor overactivity indicate that TRPA1 may have a role in sensory transduction in this organ. The study also highlights H2S as a TRPA1 activator potentially involved in inflammatory bladder disease.

Voltage-gated ion channel Nav1.7 innervation in patients with idiopathic rectal hypersensitivity and paroxysmal extreme pain disorder (familial rectal pain)

Faecal urgency and incontinence with rectal hypersensitivity is a chronic, unexplained condition that is difficult to treat. The aim of this study was to determine if there was an altered level of the voltage gated tetrodotoxin-sensitive (TTX-s) sodium channel Na(v)1.7 in rectal sensory fibres, since this channel has been implicated in clinical nociceptive disorders. Full thickness rectal biopsies from patients with physiologically characterised rectal hypersensitivity (n=7) were compared with control tissues (n=10). Formalin fixed specimens were studied by immunohistochemistry using affinity purified antibodies to Na(v)1.7 and the pan-neuronal structural marker PGP9.5, and the immunoreactive nerve fibres quantified by computerised image analysis. In rectal hypersensitivity, Na(v)1.7 immunoreactive nerve fibres were significantly increased in mucosal (P=0.0004), sub-mucosal (P=0.019), and muscle layers (P=0.0076), while PGP9.5 immunoreactive nerve fibres were increased significantly only in the mucosa (P=0.04); ratios of Na(v)1.7:PGP9.5 showed a significant increase in all layers, suggesting increased expression of Na(v)1.7, and nerve sprouting in the mucosa. The cause of this increase remains uncertain, but may be due to increase of nerve growth factor (NGF), which regulates the expression of both Na(v)1.7 and TRPV1, which we have previously reported to be increased in this condition. In paroxysmal extreme pain disorder (familial rectal pain), where the gene that encodes Na(v)1.7 is mutated, Na(v)1.7 protein was undetectable in the rectum (n=2), which suggests reduced Na(v)1.7 immunoreactivity or expression. Drugs that target Na(v)1.7-expressing nerve terminals may be useful for treating rectal hypersensitivity, and combining these with TRPV1 antagonists may enhance efficacy.

Localization and thiol dependancy of endogenous nitro compounds-mediating urethral photo-relaxation

Using a nitric oxide (NO)-specific fluorescent probe, we have examined the location of NO generation in the urethra from sheep and rat when induced by either electrical field- or light-stimulation (EFS and LS, respectively). In addition, we studied the effect of specific glutathione (GSH) modifiers, acting upon different cellular GSH pools, on NO release and on urethral relaxation. Both EFS and LS led to fluorescence emission from a fiber network associated with neuronal NO synthase (nNOS) immunoreactive nerves. Both the relaxation and the fluorescence elicited by EFS were blocked by specific nNOS inhibitors, but these parameters were not significantly modified by endogenous GSH depletion. In contrast, the opposite was found for LS-induced responses. Moreover, when the mitochondrial pool was effectively reduced by incubation with ethacrynic acid, the responses to LS were further reduced until they disappeared after intensive LS. Our results confirm that while NO is released by nNOS activation, the photolytic breakdown of an endogenous nitro-compound, probably S-nitroso-glutathione, in nitrergic nerves (and in the vascular endothelium) is the only factor responsible for photo-relaxation. The possible role of this mechanism in NO inactivation and as a protective mechanism in NO-generating structures is further discussed.

Innervation and Neurotransmitter Localization in the Lung of the Nile bichir Polypterus bichir bichir

Anatomical and functional studies of the autonomic innervation in the lung of dipnoan fishes and the bichirs are lacking. The present immunohistochemical studies demonstrated the presence of nerve fibers in the muscle layers of the lung of the bichir, Polypterus bichir bichir, and identified the immunoreactive elements of this innervation. Tyrosine hydroxylase, acetylcholinesterase, and peptide immunoreactivity was detected in the intramural nerve fibers. Extensive innervation was present in the submucosa where adenylatecyclase/activating polypeptide 38, substance P, P(2)X(2), and 5-hydroxytryptamine (5-HT)-immunoreactive nerve fibers mainly supplied blood vessels. A collection of monopolar neurons located in the submucosal and the muscular layers of the glottis expressed a variety of various transmitters. These neurons may be homologous to ganglion cells in the branchial and pharyngeal rami of the vagus in fishes. Nerves containing 5-HT and P(2)X(2) receptor immunoreactivity projected to the lung epithelium. Associated with neuroepithelial cells in mucociliated epithelium, were neuronal nitric oxide synthase-immunopositive axons. The physiological function of this innervation is not known. The present study shows that the pattern of autonomic innervation of the bichir lung may by similar in its elements to that in tetrapods.

Sympathectomy decreases size and invasiveness of tongue cancer in rats

The sympathetic nervous system plays a role in carcinogenesis wherein locally released sympathetic neurotransmitters affect proliferation, angiogenesis, vessel permeability, lymphocyte traffic and cytokine production. The present in vivo study was designed to investigate whether surgical sympathectomy, both unilateral and bilateral, had an effect on tumor growth, interstitial fluid pressure (IFP) and lymphatics in rat tongue cancer. We used 4-nitroquinoline-1-oxide (4-NQO) in drinking water for 19 weeks to induce tongue cancer in 20 Dark Agouti rats. After 11 weeks, one group underwent unilateral sympathectomy and another underwent bilateral sympathectomy, while the third group underwent sham surgery. By 19 weeks, tumors in the bilaterally sympathectomized (BL-SCGx) rats were significantly smaller ( P<0.05), more diffuse in appearance and less invasive ( P<0.05) compared with the large exophytic tumors in the sham-operated rats. The relative lymphatic area was significantly decreased ( P<0.05) in tumors in the BL-SCGx rats compared with the sham group. Interestingly, the tumors in rats that underwent unilateral or bilateral sympathectomy had a significantly lower ( P<0.05) IFP than those in sham rats. Lack of tyrosine hydroxylase (TH) immunoreactive nerves and few neuropeptide Y (NPY) positive fibers indicate absence of sympathetic nerve fibers in the bilateral sympathectomized group. The peritumoral lymph vessel area was correlated with the tumor size ( P<0.001), depth of invasion ( P<0.001), weight of rats ( P<0.005) and IFP ( P<0.05). In conclusion, the present study presents evidence that deprivation of sympathetic nerves decreases tumor growth in rat tongue, probably caused by decreasing IFP and lymph vessel area.

Immunohistochemical localization of adrenergic receptors in the rat organ of corti and spiral ganglion

Alpha(1)-, beta(1)-, and beta(2)-adrenergic receptors (ARs), which mediate responses to adrenergic input, have been immunohistochemically identified within the organ of Corti and spiral ganglion with polyclonal antibodies of established specificity. Alpha(1)-AR was immunolocalized to sites overlapping supranuclear regions of inner hair cells as well as to nerve fibers approaching the base of inner hair cells, most evident in the basal cochlear turn. A similar preponderance across cochlear turns for alpha(1)-AR in afferent cell bodies in the spiral ganglion pointed to type I afferent dendrites as a possible neural source of alpha(1)-AR beneath the inner hair cell. Foci of immunoreactivity for alpha(1)-AR, putatively neural, were found overlapping supranuclear and basal sites of outer hair cells for all turns. Beta(1)- and beta(2)-ARs were immunolocalized to sites overlapping apical and basal poles of the inner and outer hair cells, putatively neural in part, with immunoreactive nerve fibers observed passing through the habenula perforata. Beta(1)- and beta(2)-ARs were also detected in the cell bodies of Deiters' and Hensen's cells. Within the spiral ganglion, beta(1)- and beta(2)-ARs were immunolocalized to afferent cell bodies, with highest expression in the basal cochlear turn, constituting one possible neural source of receptors within the organ of Corti, specifically on type I afferent dendrites. Beta(1)- and beta(2)-ARs in Hensen's and Deiters' cells would couple to Galphas, known to be present specifically in the supporting cells. Overall, adrenergic modulation of neural/supporting cell function within the organ of Corti represents a newly considered mechanism for modifying afferent signaling.