[CLINICAL AND ENDOSCOPIC, MORPHOLOGIC AND IMMUNOHISTOCHEMICAL FEATURES OF GASTRIC ULCER IN H. PYLORI-INFECTED INDIVIDUALS RECEIVING CYTOTOXIC THERAPY]

THE PURPOSE OF THE STUDY

To determine the prognostic significance of the expression of molecules of PCNA, Bcl-2, NF-Kb and tachykinins (substance P, neurokinin A) in patients with gastric ulcer (CU) receiving cytotoxic therapy.

MATERIALS AND METHODS

Total surveyed 90 patients divided into 3. equal groups. The first comparison group consisted of patients with chronic atrophic H. pylori-associated gastritis (CAG) (30 pers.). A second control group consisted of patients with gastric ulcer (30 pers.). Third, the study group consisted of 30 people. with CU suffering from hematological malignancies, in a period of complete clinical remission of the disease and receiving supportive polychemotherapy (PCT). Patients underwent endoscopy, morphological and immunohistochemical study of the mucous membrane of the antrum and body of the stomach to detect the expression of molecules of PCNA, Bcl-2, neurokinin A, substance P and factor Nf-Kb.

RESULTS

The total level of dyspeptic syndrome on visual scale analogue in patients receiving chemotherapy and GU (GUpct) was significantly higher (p < 0.05) compared with patients with GU. It should be noted that patients with GUpct reducing clinical symptoms is much slower (p < 0.05). At the same time in 13 (43.3%) patients with GUpct determines the duration of ulcer healing, whereas in patients with GU in only 4 (13.3%) patients. Patients with GUpct more frequently (p < 0.05) were verified II and stage Ill chronic gastritis (CG), while Stage I--less (p < 0.05). Patients with GUpct significantly more often (p<0.05) was determined by the II degree of CG and significantly less (p < 0.05)--IV degree. Patients with GUpct determined significantly lower (p < 0.05), the expression performance PCNA, substance P and neurokinin A and higher (p < 0.05)--Bcl-2 and factor Nf-kB.

CONCLUSION

GU in patients receiving chemotherapy, dyspeptic syndrome is characterized by severe, advanced stage of CG on the background of relatively low severity of CG in accordance with the classification of OLGA (2008). Patients with GUpht have a significant level of violation of regeneration changes how is this atrophy, intestinal metaplasia, dysplasia of gastric mucosa association with gross violations of the processes of epithelial cell homeostasis of epithelial cells regulation after molecules PCNA, Bcl-2, NF-kB and tachykinins (substation P, neurokinin A).

Hemokinin-1 is an important mediator of endotoxin-induced acute airway inflammation in the mouse

OBJECTIVE

Hemokinin-1, the newest tachykinin encoded by the preprotachykinin C (Tac4) gene, is predominatly produced by immune cells. Similarly to substance P, it has the greatest affinity to the tachykinin NK1 receptor, but has different binding site and signaling mechanisms. Furthermore, several recent data indicate the existence of a not yet identified own receptor and divergent non-NK1-mediated actions. Since there is no information on its functions in the airways, we investigated its role in endotoxin-induced pulmonary inflammation.

METHODS

Acute pneumonitis was induced in Tac4 gene-deleted (Tac4(-/-)) mice compared to C57Bl/6 wildtypes by intranasal E. coli lipopolysaccharide (LPS). Airway responsiveness to inhaled carbachol was measured with unrestrained whole body plethysmography 24h later. Semiquantitative histopathological scoring was performed; reactive oxygen species (ROS) production was measured with luminol bioluminescence, myeloperoxidase activity with spectrophotometry, and inflammatory cytokines with Luminex.

RESULTS

All inflammatory parameters, such as histopathological alterations (perivascular edema, neutrophil/macrophage accumulation, goblet cell hyperplasia), myeloperoxidase activity, ROS production, as well as interleukin-1beta, interleukin-6, tumor necrosis factor alpha, monocyte chemoattractant protein-1 and keratinocyte chemoattractant concentrations were significantly diminished in the lung of Tac4(-/-) mice. However, bronchial hyperreactivity similarly developed in both groups. Interestingly, in LPS-treated Tac4(-/-) mouse lungs, bronchus-associated, large, follicle-like lymphoid structures developed.

CONCLUSIONS

We provide the first evidence that hemokinin-1 plays a crucial pro-inflammatory role in the lung by increasing inflammatory cell activities, and might also be a specific regulator of lymphocyte functions.

Intranasal immunization in mice with non-ionic surfactants vesicles containing HSV immunogens: a preliminary study as possible vaccine against genital herpes

The purpose of this study was to investigate the potential of intranasal immunization with non-ionic surfactant vesicles (NISV) containing either the secretory recombinant form of glycoprotein B (gBs) of herpes simplex virus type 1 or a related polylysine reach peptides (DTK) for induction of protective immunity against genital herpes infection in mice. NISV were prepared by lipid film hydration method. The mean diameter of vesicles was around 390 nm for DTK-containing NISV (DTK-NISV) and 320 nm for gB1s-containing NISV (gB1s-NISV). The encapsulation efficiency of the molecules was comprised between 57% and 70%. After 7-14 day NISV maintained stable dimensions and a drug encapsulation higher than 48%. We showed that intranasal immunization with gB1s-NISV induces gB-specific IgG antibody and lymphoproliferative responses, whereas vaccination with DTK-NISV was not able to generate a gB-specific immune response. Our results indicate that vaccination of BALB/c mice with gB1s-NISV induced Th1 responses, as characterized by increased titre of IG2a in plasma and IFN-production in CD4+ splenic cells. Intranasal immunization with gB1s-NISV could elicit 90% (almost complete) protection against a heterologous lethal vaginal challenge with herpes simplex virus type 2. These data may have implications for the development of a mucosal vaccine against genital herpes.

Tachykinins in endocrine tumors and the carcinoid syndrome

OBJECTIVE

A new antibody, active against the common tachykinin (TK) C-terminal, was used to study TK expression in patients with endocrine tumors and a possible association between plasma-TK levels and symptoms of diarrhea and flush in patients with metastasizing ileocecal serotonin-producing carcinoid tumors (MSPCs).

METHOD

TK, serotonin and chromogranin A (CgA) immunoreactivity (IR) was studied by immunohistochemistry in tissue samples from 33 midgut carcinoids and 72 other endocrine tumors. Circulating TK (P-TK) and urinary-5 hydroxyindoleacetic acid (U-5HIAA) concentrations were measured in 42 patients with MSPCs before treatment and related to symptoms in patients with the carcinoid syndrome. Circulating CgA concentrations were also measured in 39 out of the 42 patients.

RESULTS

All MSPCs displayed serotonin and strong TK expression. TK-IR was also seen in all serotonin-producing lung and appendix carcinoids. None of the other tumors examined contained TK-IR cells. Concentrations of P-TK, P-CgA, and U-5HIAA were elevated in patients experiencing daily episodes of either flush or diarrhea, when compared with patients experiencing occasional or none of these symptoms. In a Spearman partial rank test, the correlation of P-TK with daily diarrhea was independent of both U-5HIAA and CgA levels.

CONCLUSION

We found that TK synthesis occurs in serotonin-IR tumors and that P-TK levels are significantly correlated with symptoms of flush and diarrhea in patients with MSPCs. This is, to our knowledge, the first report demonstrating an independent correlation of P-TKs with carcinoid diarrhea, a symptom that is customarily regarded as serotonin mediated. Further investigations may present opportunities for new therapeutic possibilities.

Detection of stable N-terminal protachykinin A immunoreactivity in human plasma and cerebrospinal fluid

Substance P (SP) is a neuropeptide that is released from sensory nerves and several types of immune cells. It is involved in the transmission of pain and has a number of pro-inflammatory effects. Like other neuropeptides, SP is derived from a large precursor peptide, protachykinin A (PTA). Alternative splicing results in the production of four distinct PTA molecules that all contain the sequence of SP and a common N-terminal region consisting of 37 amino acids. We have developed a sandwich immunoassay using antibodies against the N-terminal part of PTA. Here we demonstrate that N-terminal PTA immunoreactivity is present in human circulation and cerebrospinal fluid (CSF). The concentration was about 90 times higher in CSF than in EDTA-plasma. Analytical reversed phase HPLC revealed that NT-PTA 1-37 is the main immunoreactivity in human circulation and CSF. Moreover, compared to the low in vitro stability of SP of less than 12 min, NT-PTA immunoreactivity is absolutely stable in EDTA-plasma and CSF for more than 48 h. As NT-PTA 1-37 is produced in stoichiometric amounts and is theoretically co-released with SP, we suggest the measurement of NT-PTA immunoreactivity as surrogate molecule for the release of bioactive SP.

Bladder inflammatory transcriptome in response to tachykinins: neurokinin 1 receptor-dependent genes and transcription regulatory elements

BACKGROUND

Tachykinins (TK), such as substance P, and their neurokinin receptors which are ubiquitously expressed in the human urinary tract, represent an endogenous system regulating bladder inflammatory, immune responses, and visceral hypersensitivity. Increasing evidence correlates alterations in the TK system with urinary tract diseases such as neurogenic bladders, outflow obstruction, idiopathic detrusor instability, and interstitial cystitis. However, despite promising effects in animal models, there seems to be no published clinical study showing that NK-receptor antagonists are an effective treatment of pain in general or urinary tract disorders, such as detrusor overactivity. In order to search for therapeutic targets that could block the tachykinin system, we set forth to determine the regulatory network downstream of NK1 receptor activation. First, NK1R-dependent transcripts were determined and used to query known databases for their respective transcription regulatory elements (TREs).

METHODS

An expression analysis was performed using urinary bladders isolated from sensitized wild type (WT) and NK1R-/- mice that were stimulated with saline, LPS, or antigen to provoke inflammation. Based on cDNA array results, NK1R-dependent genes were selected. PAINT software was used to query TRANSFAC database and to retrieve upstream TREs that were confirmed by electrophoretic mobility shift assays.

RESULTS

The regulatory network of TREs driving NK1R-dependent genes presented cRel in a central position driving 22% of all genes, followed by AP-1, NF-kappaB, v-Myb, CRE-BP1/c-Jun, USF, Pax-6, Efr-1, Egr-3, and AREB6. A comparison between NK1R-dependent and NK1R-independent genes revealed Nkx-2.5 as a unique discriminator. In the presence of NK1R, Nkx2-5 _01 was significantly correlated with 36 transcripts which included several candidates for mediating bladder development (FGF) and inflammation (PAR-3, IL-1R, IL-6, alpha-NGF, TSP2). In the absence of NK1R, the matrix Nkx2-5_02 had a predominant participation driving 8 transcripts, which includes those involved in cancer (EYA1, Trail, HSF1, and ELK-1), smooth-to-skeletal muscle trans-differentiation, and Z01, a tight-junction protein, expression. Electrophoretic mobility shift assays confirmed that, in the mouse urinary bladder, activation of NK1R by substance P (SP) induces both NKx-2.5 and NF-kappaB translocations.

CONCLUSION

This is the first report describing a role for Nkx2.5 in the urinary tract. As Nkx2.5 is the unique discriminator of NK1R-modulated inflammation, it can be imagined that in the near future, new based therapies selective for controlling Nkx2.5 activity in the urinary tract may be used in the treatment in a number of bladder disorders.

Stromal Derived Growth Factor-1α: Another Mediator in Neural-Emerging Immune System throughTac1Expression in Bone Marrow Stromal Cells

Stromal cell-derived growth factor-1alpha (SDF-1alpha) is a member of the CXC chemokines and interacts with the G protein, seven-transmembrane CXCR4 receptor. SDF-1alpha acts as a chemoattractant for immune and hemopoietic cells. The Tac1 gene encodes peptides belonging to the tachykinin family with substance P being the predominant member. Both SDF-1alpha and Tac1 peptides are relevant hemopoietic regulators. This study investigated the effects of SDF-1alpha on Tac1 expression in the major hemopoietic supporting cells, the bone marrow stroma, and addresses the consequence to hemopoiesis. Reporter gene assays with the 5' flanking region of Tac1 showed a bell-shaped effect of SDF-1alpha on luciferase activity with 20 ng/ml SDF-1alpha acting as stimulator, whereas 50 and 100 ng/ml SDF-1alpha acted as inhibitors. Gel shift assays and transfection with wild-type and mutant IkappaB indicate NF-kappaB as a mediator in the repressive effects at 50 and 100 ng/ml SDF-1alpha. Northern analyses and ELISA showed correlations among reporter gene activities, mRNA (beta-preprotachykinin I), and protein levels for substance P. Of relevance is the novel finding by long-term culture-initiating cell assays that showed an indirect effect of SDF-1alpha on hemopoiesis through substance P production. The results also showed neurokinin 1 and not neurokinin 2 as the relevant receptor. Another crucial finding is that substance P does not regulate the production of SDF-1alpha in stroma. The studies indicate that SDF-1alpha levels above baseline production in bone marrow stroma induce the production of substance P to stimulate hemopoiesis. Substance P, however, does not act as autocrine stimulator to induce the production of SDF-1alpha. This study adds SDF-1alpha as a mediator within the neural-immune-hemopoietic axis.

Allergic airway inflammation induces tachykinin peptides expression in vagal sensory neurons innervating mouse airways

BACKGROUND

Allergic airway inflammation has been shown to induce pro-inflammatory neuropeptides such as tachykinin peptides substance P (SP) and neurokinin A (NKA) together with related peptide like calcitonin gene-related peptide (CGRP) in nodose sensory neurons innervating guinea-pig airways.

OBJECTIVE

The present study was designed to examine the effects of allergen sensitization and challenge on the SP/NKA expression in the jugular-nodose ganglion neurons innervating the murine airways.

METHODS

Using retrograde neuronal tracing technique in combination with double-labelling immunohistochemistry, the expression of SP/NKA was investigated in a murine model of allergic airway inflammation.

RESULTS

Allergic airway inflammation was found to induce the expression of SP/NKA (13.2+/-1.43% vs. 5.8+/-0.37%, P<0.01) in large-diameter (>20 microm) vagal sensory neurons retrograde labelled with Fast blue dye from the main stem bronchi.

CONCLUSION

Based on the induction of tachykinins in airway-specific large-sized jugular-nodose ganglia neurons by allergic airway inflammation, the present study suggests that allergen sensitization and challenge may lead to de novo induction of tachykinins in neurons. This may partly contribute to the pathogenesis of airways diseases such as allergic airway inflammation.

Neuroimmunological findings in allergic skin diseases

PURPOSE OF REVIEW

Recent studies have gained widespread information about the complex regulation of genetic, environmental, immunologic, and pharmacologic factors that contribute to the development of allergic inflammatory skin diseases such as atopic dermatitis. Neuroimmune mechanisms, however, still remain to be elucidated. This review will focus on the interaction between the cutaneous immune and peripheral nervous system in allergic inflammatory skin such as atopic dermatitis.

RECENT FINDINGS

Neuropeptides and neuropeptide-positive nerve fibres are prominently increased in lesions of atopic dermatitis. The density of nerve fibres is increased while peripheral nerve endings are in an active state of excitation. In this regard, neurotrophins particularly described for their functional role on nerve cells are also expressed in atopic dermatitis skin. In addition, neurotrophins modulate the functional role of eosinophils as main target effector cells in atopic dermatitis, as described recently. Interestingly, eosinophils are capable of neurotrophin as well as neuropeptide production itself, pointing to a bidirectional communication between neuronal cell populations and main target effector cells.

SUMMARY

Neurotrophins and neuropeptides modulate both the functional activity of sensory neurons and immune cells. We have therefore developed the concept of a neuroimmune network between target effector cells and sensory nerves that links pathogenic events to dysfunctions of the cutaneous immune and peripheral nervous system in allergic inflammatory skin diseases.

Pathophysiology of airway viral infections

Viral infections are major causes of cough. Virus-induced changes in airway sensory nerve function include increased tachykinin expression and, more specifically, expression of tachykinins by Adelta fibers. This change may be mediated by neurotrophins produced in response to viral infection. At the same time, activity of neutral endopeptidase, an enzyme that is important in degrading and inactivating tachykinins, is decreased by airway viral infections. Viral infections can activate eosinophils, releasing proteins that can cause tachykinin release. Moreover, expression of the NK1 receptor is increased by viral infections of the lungs. The expression of M2 muscarinic receptors, which normally decrease the sensitivity of sensory nerves, is decreased by viral infections. So it is possible that viral infections (1) increase expression of tachykinins (by causing neurotrophin expression), (2) increase release of tachykinins (by causing release of eosinophil proteins), (3) decrease degradation of tachykinins (by decreasing neutral endopeptidase activity), (4) increase expression of the NK1 receptor (again mediated by neurotrophins), and (5) increase the sensitivity of airway afferents (by decreasing M2 muscarinic receptor expression). All these changes may potentiate the tachykininergic input into the cough reflex, and may provide new therapeutic targets for controlling virus-induced cough.

The role of neural inflammation in asthma and chronic obstructive pulmonary disease

The tachykinins substance P and neurokinin A are found within airway nerves and immune cells. They have various effects on the airways that can contribute to the changes observed in asthma and chronic obstructive pulmonary disease. Both tachykinin NK(1) and NK(2) receptors have been involved in the bronchoconstriction and the proinflammatory changes induced by substance P and neurokinin A. Tachykinin NK(1) and NK(2) receptor antagonists have activity in various animal models of allergic asthma and chronic bronchitis. It is suggested that dual NK(1)/NK(2) and triple NK(1)/NK(2)/NK(3) tachykinin receptor antagonists have potential in the treatment of obstructive airway diseases.

Progesterone and norethisterone have different effects on tachykinin-like immunoreactivity in rat cortex and striatum

OBJECTIVE

The purpose of this study was to investigate the effects of progesterone and the most commonly prescribed synthetic progestogen, norethisterone, on regional immune-like reactivity of neuropeptide Y (NPY), substance P (SP), neurokinin A (NKA) and neurotensin (NT) in brains of female ovariectomized estradiol-substituted rats.

RESULTS

Norethisterone+estradiol-treated rats had 44% lower SP levels compared with estradiol-only-treated in frontal cortex and 20% lower NKA levels in comparison with progesterone+estradiol-treated in frontal cortex. Progesterone+estradiol-treated rats had 66% lower SP levels in striatum in comparison with both estradiol-only-treated and norethisterone+estradiol-treated. No significant results were found for NPY and NT.

CONCLUSION

Progesterone and the synthetic progestogen, norethisterone, have different effects on SP- and NKA-like immunoreactivity in rat cortex and striatum. The effects of NET on SP- and NKA-like immunoreactivity in frontal cortex may contribute to the mood effects ascribed to this progestogen in clinical usage.

Inflammation-induced plasticity of the afferent innervation of the airways

The activation of primary afferent neurons that innervate the airways leads to homeostatic and defensive reflexes. The anatomic and physiologic characteristics of these afferent fibers do not appear to be static properties but rather appear to change rapidly in response to inflammation. The threshold for activation of airway afferent neurons to various stimuli, for example, is not fixed; these fibers can be become sensitized during inflammation. A subset of nociceptive-like (C-fibers) airway afferent neurons not only participates in centrally mediated reflexes but is also thought to release neuropeptides at their peripheral terminals, leading to neurogenic inflammation. An increase in the content of tachykinins is commonly seen in inflamed tissues, and there is accumulating evidence that irritation and inflammation of the airways is associated with the induction of tachykinin synthesis in non-nociceptive airway afferent fibers that under normal conditions do not contain neuropeptides. The release of neurokinins from the peripheral terminals in the airways and their central terminals in the brain stem may contribute to the symptoms of inflammatory airway diseases. Elevated release of neurokinins from peripheral terminals may promote local inflammatory responses, and the release of neurokinins in the brainstem, together with inflammation-induced increases in the excitability of afferent fibers, may culminate in altered visceral autonomic reflex activity, changes in breathing pattern, and cough.

Increased tachykinin NK(1) receptor immunoreactivity in the prefrontal cortex in schizophrenia

BACKGROUND

Changes in levels of substance P and substance P-binding sites have been implicated in schizophrenia. However, no studies have used receptor-specific antibodies to directly investigate the substance P (neurokinin 1) receptor in schizophrenia.

METHODS

We used an antibody directed against the human neurokinin-1 receptor to compare the distribution of neurokinin-1 receptors in the prefrontal cortices from six subjects with schizophrenia and six control subjects, matched for age, gender, and postmortem interval.

RESULTS

In control tissue, dots of neurokinin-1 receptor immunoreactivity were observed in layer I to upper/mid layer III only. In contrast, dots of neurokinin-1 receptor immunoreactivity were observed in all layers of the prefrontal cortex in subjects with schizophrenia, and the density of dots was significantly greater than in control subjects.

CONCLUSIONS

This is the first report of increased neurokinin-1 receptor immunoreactivity in the prefrontal cortex in subjects with schizophrenia. These changes may have implications for understanding the pathophysiology of the prefrontal cortex in schizophrenia and for the treatment of this disorder.

Fenvalerate treatment affects development of olfactory glomeruli in Manduca sexta

Low doses of fenvalerate, a widely used type-II pyrethroid insecticide, have been shown previously to produce abnormal olfactory centers in the brain and abnormal olfactory-mediated behavior in beetles (Wegerhoff et al. [1998] Neuroreport 9:3241-3245). Here, we use the experimental advantages of the moth Manduca sexta to explore the cellular changes that lead to these abnormalities. Our results indicate that treatment with fenvalerate may affect multiple aspects of the development of the primary olfactory centers, the antennal lobes, in Manduca, including ingrowth of olfactory receptor axons, axon fasciculation, and targeting within the antennal lobe, and intercellular signaling between the receptor axons and the glial cells that ordinarily surround and stabilize the developing olfactory glomeruli.

Hemokinin is a hematopoietic-specific tachykinin that regulates B lymphopoiesis

We report here the molecular cloning of a newly identified preprotachykinin gene, Pptc, which specifies the sequence for a new preprotachykinin protein and bioactive peptide designated hemokinin 1 (HK-1). PPT-C mRNA was detected primarily in hematopoietic cells in contrast to the previously described Ppta and Pptb genes, which are predominantly expressed in neuronal tissues. HK-1 has several biological activities that are similar to the most studied tachykinin, substance P, such as induction of plasma extravasation and mast cell degranulation. However, HK-1 also has properties that are indicative of a critical role in mouse B cell development. HK-1 stimulated the proliferation of interleukin 7-expanded B cell precursors, whereas substance P had no effect. HK-1, but not substance P, promoted the survival of freshly isolated bone marrow B lineage cells or cultured, lipopolysaccharide-stimulated pre-B cells. N-acetyl-L-trytophan-3,5-bistrifluromethyl benzyl ester, a tachykinin receptor antagonist, increased apoptosis of these cells and in vivo administration of this antagonist led to specific reductions of the B220lowCD43 population (the pre-B cell compartment) in the bone marrow and the IgMhighIgDlow population (the newly generated B cells) in the spleen. Thus, HK-1 may be an autocrine factor that is important for the survival of B cell precursors at a critical phase of development.

Airway neutrophils and interleukin-17

It is well known that exacerbations of obstructive airways disease such as asthma and chronic obstructive pulmonary disease are associated with an increased number of neutrophils in the airways. However, the mechanisms behind this phenomenon are poorly understood. There is in vivo experimental evidence that the number of airway neutrophils is controlled by certain T-lymphocytes, but the mediators responsible for this lymphocyte-related neutrophilia have not yet been identified. In this review, novel evidence that the T-lymphocyte-related cytokine interleukin (IL)-17 can link the activation of certain T-lymphocytes to the recruitment and activation of airway neutrophils is described. The IL-17-induced neutrophil recruitment is mediated via induced CXC chemokine release through steroid-sensitive mechanisms and is modulated by release of endogenous tachykinins. These effects of IL-17 are potentiated by other pro-inflammatory cytokines such as (IL-1beta) and tumour necrosis factor-alpha. Clinical studies are needed to evaluate whether or not targeting these mechanisms can provide a useful pharmacotherapeutical approach against exaggerated mobilization of neutrophils in obstructive airways disease.

Tachykinin-related peptide and GABA-mediated presynaptic inhibition of crayfish photoreceptors

Off-axis illumination elicits lateral inhibition at the primary visual synapse in crustacea and insects. The evidence suggests that the inhibitory action is presynaptic (i.e., on the photoreceptor terminal) and that the amacrine neurons of the lamina ganglionaris (the first synaptic layer) may be part of the inhibitory pathway. The neurotransmitters and the synaptic mechanisms are unknown. We show by immunocytochemistry that GABA and a tachykinin-related peptide (TRP) are localized in the amacrine neurons of the crayfish lamina ganglionaris. Indirect evidence suggests that GABA and TRP may be colocalized in these neurons. The extensive processes of the amacrine neurons occupy lamina layers containing the terminals of photoreceptors. Application of exogenous GABA and TRP to photoreceptor terminals produces a short-latency, dose-dependent hyperpolarization with a decay time constant on the order of a few seconds. TRP also exhibits actions that evolve over several minutes. These include a reduction of the receptor potential (and the light-elicited current) by approximately 40% and potentiation of the action of GABA by approximately 100%. The mechanisms of TRP action in crayfish are not known, but a plausible pathway is a TRP-dependent elevation of intracellular Ca(2+) that reduces photoreceptor sensitivity in arthropods. Although the mechanisms are not established, the results indicate that in crayfish photoreceptors TRP displays actions on two time scales and can exert profound modulatory control over cell function.

Differential modulation of human immunoglobulin isotype production by the neuropeptides substance P, NKA and NKB

The modifying effects of tachykinins substance P, neurokinin A and neurokinin B on immunoglobulin production were analyzed in an in vitro culture system. Purified human T- and B-cells were stimulated with TGFbeta2 and IL-5 to induce preferential IgA production. Neuropeptides had the following effects. (1) The levels of IgA and IgG4 production were enhanced by IL-5 and TGFbeta2; IgA levels remained constant or were slightly augmented by neuropeptides, whereas IgG4 was further augmented. (2) IL-5 and TGFbeta2 did not alter IgG3 production, but neuropeptides stimulated secretion of this subclass. (3) IgG1 and IgM production were inhibited by IL-5 and TGFbeta2. This effect was prevented by neuropeptides. (4) Other isotypes including IgG2 and IgE remained unaffected. Except for IgM, these effects were blocked by specific receptor antagonists indicating specificity. The tachykinin receptor NK-1 mRNA was detected in B- and T-cells, whereas NK-3 mRNA was only present in T- and B-cell coculture following activation. Furthermore, neuropeptide effects depended on cytokine co-stimulation and the presence of T-cells. These results suggest that neuropeptides are potent modifiers of preferential IgA synthesis.

Mosquito feeding modulates Th1 and Th2 cytokines in flavivirus susceptible mice: an effect mimicked by injection of sialokinins, but not demonstrated in flavivirus resistant mice

Culex pipiens and Aedes aegypti mosquitoes were fed on C3H/HeJ mice and systemic cytokine production was quantified from stimulated lymphocytes harvested four to ten days after feeding. Mosquito feeding on C3H/HeJ mice significantly down regulated IFN gamma production seven to ten days post feeding by Cx. pipiens and seven days after Ae aegypti feeding. Th2 cytokines, IL-4 and IL-10, were significantly up regulated 4-7 days after Cx. pipiens and Ae. aegypti feeding. The immunosuppressive effect of Cx. pipiens feeding on systemic cytokine production was not evident in congenic flavivirus resistant (C3H/RV) mice, as systemic IFN gamma and IL-2 were significantly up regulated at days 7 and 10, correlating with a significant decrease in IL-4 10 days after feeding by Cx. pipiens mosquitoes. Inoculation of 5-1000 ng of sialokinin-I into C3H/HeJ mice mimicked the effect of Ae. aegypti feeding by down regulating Th1 cytokines and significantly up regulating Th2 cytokines four days post inoculation. Injections of sialokinin-II resulted in only moderate effects on IFN gamma and IL-4 production seven and ten days after injection. Thus natural feeding by two arbovirus vectors had a profound T cell modulatory effect in vivo in virus susceptible animals which was not demonstrated in the flavivirus resistant host. Moreover, sialokinin-I and sialokinin-II mimicked the effect of mosquito feeding by modulating the host T cell response. These results may lend new insight into specific aspects of the role of the mosquito vector in potentiating virus transmission in the mammalian host.

Identification of a delta isoform of preprotachykinin mRNA in human mononuclear phagocytes and lymphocytes

We have characterized preprotachykinin (PPT-A) gene transcript splicing products and identified a fourth isoform of PPT-A mRNA transcript in human peripheral blood-isolated monocytes and PBL. Using RT-PCR, Southern blot analysis and nucleotide sequencing analysis, we have identified the four isoforms of PPT-A transcripts (alpha, beta, gamma and delta) in human peripheral blood-isolated monocytes and PBL. The delta-PPT transcript present in the immune cells lacks exons 4 and 6. The sequences of exons 3, 5 and 7 of delta-PPT transcript completely match those of beta-PPT transcript. The alpha-PPT and beta-PPT sequences in these cells are identical to those obtained by Tan and Too (GenBank accession number U37539) and Harmar et al. (Genbank accession number X54469), but differ by a single nucleotide from another entry by Chiwakata et al. (Genbank accession number M68906). In comparison to this latter sequence, there was a C-->T change at amino acid position 87 (CCT-->CTT) which may result in a Pro to Leu change. Identification of the new SP mRNA transcript in both human CNS and immune cells supports the concept of an important biological link between CNS and immune system.

Effects of silica exposure on substance P immunoreactivity and preprotachykinin mRNA expression in trigeminal sensory neurons in Fischer 344 rats

Trigeminal sensory neurons innervate the nasal cavity and may release substance P (SP) upon exposure to inhaled irritants. The purpose of this study was to determine if silica dust, an occupational irritant causing inflammation, activates sensory neurons supplying the nasal cavity. Male Fischer 344 rats were placed in inhalation chambers and exposed daily to 2 mg/m3 of fresh silica (average diameter 1 microm) for 6 mo. Following exposure, the trigeminal ganglia (TG) were removed and prepared for SP immunocytochemistry and for preprotachykinin (PPT) autoradiographic in situ hybridization. The SP-like immunofluorescence in TG neurons was subjectively categorized as high, moderate, or low (background) intensity. In situ hybridization autoradiographs were quantified on the basis of grain density using digital imaging analysis. The SP immunoreactivity and PPT mRNA expression in the TG neurons were significantly increased after silica inhalation. The proportion of highly positive SP-immunoreactive neurons shifted from 1.30 +/- 0.58% in controls to 11.30 +/- 1.15% after silica treatment. The neurons exhibiting high grain density for PPT mRNA increased from 1.50 +/- 0.87% in controls to 11.67 +/- 0.58% in the silica group. Thus, inhalation of silica causes upper airway irritation resulting in increased levels of immunoreactive neuronal SP and PPT mRNA. These findings suggest that silica activates sensory pathways that may be involved in nasal inflammation.

Peptidergic activation of locust dorsal unpaired median neurons: depolarization induced by locustatachykinins may be mediated by cyclic AMP

Four tachykinin-related peptides, locustatachykinin 1-4 (LomTK 1-4) are distributed in interneurons throughout the central nervous system of the locust Locusta migratoria and may have important roles as neurotransmitters or neuromodulators. In search of the central actions of LomTKs, we analyzed the response of the efferent dorsal unpaired median (DUM) neurons in the locust metathoracic ganglion. Immunocytochemistry, using an antiserum against LomTK 1, combined with intracellular filling of efferent DUM neurons with Lucifer yellow, revealed that LomTK-immunoreactive fibers are in close proximity to dendritic arborizations of the DUM neurons. Hence, LomTKs may act on DUM neurons by releasing locally in the metathoracic ganglion. Intracellular recordings were made from somata of DUM neurons, and LomTKs were either bath-applied to an isolated metathoracic ganglion or pressure-ejected onto the DUM neuron soma. LomTK 1 at concentrations of 0.1 mM-0.1 microM caused a relatively slow, reversible depolarization with a subsequent increase in the frequency of action potential firing. Amino-terminally truncated forms of LomTK 1 were applied to DUM neurons. The heptapeptide [3-9]-LomTK 1 had a substantially reduced activity, and bioactivity was lost after further truncation. Spantide 1, an antagonist of mammalian tachykinin receptors, reversibly blocked the effect of LomTK 1. The effect of LomTK 1 was clearly reduced in the presence of GDP-beta-S, a stable analog of GDP that inactivates G-proteins. The action of LomTK 1 was potentiated by both IBMX and theophylline, two cyclic AMP (cAMP) phosphodiesterase inhibitors. The action of LomTK 1 was mimicked by pressure-ejecting 8-bromo-cAMP, a membrane permeable analog of cAMP, and by forskolin, an adenylate cyclase activator. Furthermore, cAMPS, a blocker of protein kinase A activity, reduced the effect of LomTK 1. These findings indicate that cAMP is involved in mediating DUM neuron depolarization.

Tachykinins contribute to the acute airways response to allergen in sheep actively sensitized to Ascaris suum

Tachykinins, found in sensory nerves, have effects in the airways which suggest that they may contribute to the pathogenesis of asthma. We aimed to find evidence for tachykinin involvement in the immediate airway response to allergen in a sheep model of experimental asthma. Twenty-four sheep were actively sensitized to Ascaris suum, then challenged with nebulized Ascaris extract in a dose-response fashion. Change in lung resistance (RL) in response to challenge was measured. Responder sheep (those with an increase in RL of > or = 100% over baseline) that had reproducible responses over three challenges were identified (n = 4 sheep) and a PC100 (number of breaths of extract required to induce a 100% increase in RL) was determined. The effect of the neutral endopeptidase inhibitor phosphoramidon, the NK-1 receptor-specific antagonist CP 96, 345 and capsaicin desensitization on the RL response to Ascaris challenge was then assessed. Administration of phosphoramidon before Ascaris decreased the PC100 to 31 +/- 7% of the PC100 seen with Ascaris alone (P < 0.05), whereas CP 96,345 and capsaicin desensitization increased the PC100 to 285 +/- 41% and 555 +/- 93% respectively (P < 0.05 for both). These findings suggest that endogenous tachykinins are released in response to allergen challenge and that they contribute to the immediate increase in RL.

Morphologic maturation of tachykinin peptide-expressing cells in the postnatal rabbit retina

Tachykinin (TK) peptides, which include substance P, neurokinin A, two neurokinin A-related peptides and neurokinin B, are widely present in the nervous system, including the retina, where they act as neurotransmitters/modulators as well as growth factors. In the present study, we investigated the maturation of TK-immunoreactive (IR) cells in the rabbit retina with the aim of further contributing to the knowledge of the development of transmitter-identified retinal cell populations. In the adult retina, the pattern of TK immunostaining is consistent with the presence of TK peptides in amacrine, displaced amacrine, interplexiform and ganglion cells. In the newborn retina, intensely immunostained TK-IR somata are located in the ganglion cell layer (GCL) and in the inner nuclear layer (INL) adjacent to the inner plexiform layer (IPL). They are characterized by an oval-shaped cell body originating a single process without ramifications. TK-IR processes are occasionally observed in the IPL and in the outer plexiform layer (OPL). Long TK-IR fiber bundles are observed in the ganglion cell axon layer. TK-IR profiles resembling small somata are rarely observed in the INL adjacent to the OPL. At postnatal day (PND) 2, some TK-IR cells display more complex morphologic features, including processes with secondary ramifications. Long TK-IR processes in the IPL are often seen to terminate with growth cones. Between PND 6 and PND 11 (eye opening), there is a dramatic increase in the number of immunolabeled processes with growth cones both in the IPL and in the OPL and the mature lamination of TK-IR fibers in laminae 1, 3 and 5 of the IPL is established. TK-IR cells attain mature morphological characteristics and the rare, putative TK-IR somata in the distal INL are no longer observed. After eye opening, growth cones are not present and the pattern typical of the adult is reached. These observations indicate that the development of TK-IR cells can be divided into an early phase (from birth to PND 6) in which these cells establish their morphological characteristics, and a later phase (from PND 6 to eye opening) in which they are involved in active growth of their processes and likely in synapse formation. Since TK peptides are thought to play neurotrophic actions in the developing nervous system and they are consistently present in the retina throughout postnatal development, they may also act as growth factors during retinal maturation.

Characterization of antisera specific to NK1, NK2, and NK3 neurokinin receptors and their utilization to localize receptors in the rat gastrointestinal tract

Understanding the physiological role of tachykinins requires precise cellular and subcellular localization of their receptors. We raised antisera by immunizing rabbits with peptides corresponding to portions of the intracellular tails of the rat neurokinin 1, 2, and 3 receptors (NK1-R, NK2-R, NK3-R). Receptors were localized by immunofluorescence and confocal microscopy. NK1-R, NK2-R, and NK3-R were detected at the plasma membrane of transfected cells with minimal intracellular stores. Staining was abolished by preabsorption of the antisera with the peptides used for immunization. Nontransfected cells were unstained. Each antiserum only stained cells transfected with the appropriate receptor and did not stain cells transfected with the other receptors. Therefore, the antisera are specific and do not cross-react with other neurokinin receptors. We examined the distribution of the neurokinin receptors in the gastrointestinal tract of the rat. NK1-R was detected in myenteric and submucosal neurons and in interstitial cells of Cajal. NK2-R was localized to circular and longitudinal muscle cells and to nerve endings in the plexuses. NK3-R was detected in numerous myenteric and submucosal neurons. Some neurons expressed both NK1-R and NK3-R. Receptors were detected at the plasma membrane and in endosomes. Cells expressing the receptors were closely associated with tachykinin-containing nerve fibers. Thus, NK1-R and NK3-R mediate neurotransmission by tachykinins within enteric nerve plexuses, and NK1-R and NK2-R mediate the effects of tachykinins on interstitial and smooth muscle cells, respectively.

Calretinin immunoreactivity of motor neurons in the guinea-pig distal colon and taenia coli

Calretinin is a calcium-binding protein which occurs in neurons and endocrine cells, including neurons throughout the gastrointestinal tract. Calretinin-immunoreactive (IR) neurons innervate the circular muscle in the guinea-pig distal colon and have descending as well as ascending projections. This suggests that calretinin-IR is in motor neurons, but whether it might be in excitatory or inhibitory motor neurons or both was previously undetermined. The presence of calretinin-IR in neurons innervating the taenia coli has not been previously reported. Numerous fibres in the circular muscle of the distal colon and in the taenia coli displayed immunoreactivity for calretinin. Tachykinin (TK), vasoactive intestinal peptide (VIP), calretinin, and gamma-aminobutyric acid (GABA) immunoreactivity was also in fibres innervating these targets. The abundances of these fibres was estimated to be TK > VIP > calretinin > GABA. Double label immunohistochemistry revealed the presence in both tissues of populations of calretinin-IR fibres which were also TK-IR, and fibres with calretinin and GABA-IR in the colon, but calretinin-IR fibres were never VIP-IR. TK- and VIP-IR were in separate populations of nerve fibres as were GABA- and TK-IR. It is concluded that calretinin-IR does not provide a definitive labelling of a physiologically known subgroup of motor neurons, either in the distal colon or in the taenia coli, but that calretinin is most likely to be in excitatory motor neurons.

Recognition of neurokinin 1 receptor (NK1-R): an antibody to a peptide sequence from the third extracellular region binds to brain NK1-R

Substance P (SP) can produce cytokine-like responses by astrocytes and mononuclear cells. In an effort to identify neurokinin-1-receptors (NK1-R), an antibody to NK1-R was generated by using a linear peptide sequence from the deduced third extracellular region (ECR) corresponding to the seven transmembrane rat brain NK1-R. The ECR-3 peptide was coupled to keyhole-limpet hemocyanin and the antisera produced in rabbits was purified by binding to a peptide-affinity matrix. The specificity for the anti-peptide antibody was shown by its reactivity to the ECR-3 peptide by ELISA. The anti-ECR-3 peptide antibody could detect, by Western blot analysis of SDS-PAGE-separated rat brain membranes, a single band with an apparent molecular weight (MW) of 53-54 kDa. An affinity matrix made from the anti-ECR-3 antibody was used to isolate NK1-R from rat brain membranes which exhibited two products on SDS-PAGE with apparent MW of 54 and 44 kDa. The C6 astrocytes were shown to express NK1-R as determined by [125I]Bolten-Hunter SP binding to intact cells with a Kd = 0.32 nM. These C6 cells did not co-express either NK2-R or NK3-R when analyzed at the mRNA level. The anti-ECR-3 peptide antibody could inhibit [125I]Bolten-Hunter SP binding to intact C6 astrocytes and CHO cells expressing NK1-R by greater than 95% when compared to normal rabbit IgG which failed to inhibit radiolabeled SP binding. Thus, an antibody which recognizes surface determinants to the NK1-R could be generated upon immunization with an NK1-R peptide.

GABA and nitric oxide synthase immunoreactivities are colocalized in a subset of inhibitory motor neurons of the guinea-pig small intestine

Simultaneous immunofluorescence labelling was used to determine the patterns of colocalization of immunoreactivity for gamma-aminobutyric acid (GABA-IR) with immunoreactivity for nitric oxide synthase (NOS), vasoactive intestinal peptide (VIP) and tachykinins (TK) in nerve cells and fibres of the guinea-pig small intestine. GABA-IR nerve cell bodies were located in the myenteric plexus and varicose fibres innervated the circular and longitudinal muscle, but did not form pericellular endings in the myenteric ganglia. GABA-IR nerve cells comprised 4-5% of all nerve cells in the myenteric ganglia. Of GABA-IR myenteric nerve cells, about 85% had NOS-IR and of GABA-IR nerve fibres in both muscle layers, about 75% were NOS-IR. Conversely, 20% of NOS-IR nerve cells were GABA-IR. About 6% of GABA-IR nerve fibres innervating the circular muscle, but none innervating the longitudinal muscle, were TK-IR. Most GABA-IR fibres supplying the circular muscle, but none of those supplying the longitudinal muscle, were VIP-IR. From this study, and previous studies of projections of enteric neurons, it is concluded that most GABA-IR neurons in the guinea-pig small intestine are inhibitory motor neurons that also contain NOS-IR. A small proportion represents anally directed excitatory motor neurons that innervate the circular muscle and are also immunoreactive for TK.

Immunoreactive tachykinins in 24-h collections of urine from patients with carcinoid tumours: characterization and correlation with plasma concentrations

Tachykinins are a family of peptides that may be present in and secreted from carcinoid tumours of mid-gut origin. They are likely to play a role in the pathogenesis of, e.g. the flush, dyspnoea and valvular heart disease seen in the carcinoid syndrome. Since tachykinins are secreted from the tumour into the circulation in bursts, coinciding with flushing attacks, and have short half-lives, we anticipated that analysis of 24-h urine excretion of immunoreactive tachykinin metabolites might prove to be a more sensitive and stable parameter for monitoring than tachykinin-like immunoreactivity in plasma. The study included 48 patients hospitalized for treatment of advanced carcinoid tumours and 32 healthy controls. The urine excretion of tachykinin-like immunoreactive metabolites in the carcinoid patients (median 27.5 pmol 24 h-1, interquartile range (IQR) 8.5-51.0 pmol 24 h-1) was significantly (p<0.001) higher than that in the 32 healthy subjects (median 3.0 pmol 24 h-1, IQR 0.9-4.20 pmol 24 h-1). Of the patients, 38 (79%) had elevated 24-h urine excretion of tachykinin-like immunoreactive metabolites while 31 (64%) had elevated plasma concentrations of tachykinin-like immunoreactive metabolites. Of the patients, 27 (56%) had elevated concentrations of tachykinin-like immunoreactive metabolites both in plasma and urine, 12 (25%) had elevated concentrations only in urine excretion, 3 (6%) had elevated concentrations of only plasma tachykinin-like immunoreactive metabolites and 7 (14%) had elevation of neither plasma nor urine concentrations. Analysis by means of different column chromatographic techniques indicated that the immunoreactive material was heterogeneous, with some components co-eluting with oxidized neurokinin A (NKA) and neuropeptide K (NPK). The urine tachykinin-like immunoreactivity correlates well with that of plasma, but is a slightly more sensitive indicator of elevated tachykinin-like immunoreactivity, probably since levels of urine tachykinin-like immunoreactive metabolites reflect the overall amount of the latter secreted into the circulation during 24 h.

Abundant distribution of locustatachykinin-like peptide in the nervous system and intestine of the cockroach Leucophaea maderae

An antiserum raised to the locust neuropeptide locustatachykinin I (LomTK I) was used for analysis of the distribution of tachykinin-related peptide in the cockroach Leucophaea maderae. Extracts of dissected brains, suboesophageal ganglia, thoracic ganglia and midguts were separated by high performance liquid chromatography and the fractions analysed in enzyme-linked immunosorbent assay with use of the LomTK antiserum. Each of the tissues was found to contain LomTK-like immunoreactive (LomTK-LI) components with retention times corresponding approximately to synthetic LomTK I and II and callitachykinins I and II. The LomTK antiserum was also used for immunocytochemical mapping of peptide in the nervous system and intestine of L. maderae. A large number of LomTK-LI interneurons were detected in the proto-, deuto- and tritocerebrum of the brain and in the suboesophaegeal ganglion. The immunoreactive neurons supply processes to most parts of the brain: the central body, protocerebral bridge, mushroom body calyces, antennal lobes, optic lobe and most regions of the non-glomerular neuropil. A few protocerebral neurons send LomTK-LI processes to the glandular lobe of the corpora cardiaca. In each of the thoracic ganglia there are six LomTK-LI interneurons and in each of the unfused abdominal ones there are two interneurons. The fused terminal ganglion contains some additional cell bodies in the posterior neuromers. LomTK-LI cell bodies were detected in the frontal ganglion and fibres were seen in this ganglion as well as in the hypocerebral ganglion. The frontal ganglion supplies LomTK-LI processes to the muscle layer of the pharynx. The muscle layer of the midgut is innervated by LomTK-LI fibres from the stomatogastric system (oesophageal nerve and associated ganglia). Additionally the midgut contains numerous LomTK-LI endocrine cells. A number of the pharyngeal dilator muscles were also found to be innervated by LomTK-LI fibres, probably derived from cell bodies in the suboesophageal ganglion. All the LomTK-LI neurons of the central nervous system appear to be interneurons, suggesting a neuromodulatory role of the endogenous tachykinins. The tachykinin-like peptides from peripheral ganglia may be involved in the control of foregut and midgut contractility and possibly the peptide of the endocrine cells in the midgut has additional actions related to intestinal function.

Multiple molecular forms of tachykinins in rat spinal cord: a study comparing different extraction methods

Various procedures for extraction at acid, neutral and alkaline pH were compared with regard to the yield of different tachykinins and tachykinin-like substances from rat spinal cord. Reverse phase high performance liquid chromatography (RP-HPLC) and radioimmunoassay with various C-terminally directed tachykinin antisera and a newly developed N-terminally directed substance P (SP)-antiserum (SPN 1) were used. Antiserum SPN 1 fully reacts with SP-analogues modified at the C-terminal end (SP free acid and SP-Gly-Lys) and also (77%) with SP(1-9) but not with C-terminal SP-fragments lacking 2 or more N-terminal amino acids. The highest levels of SP-like immunoreactivity (LI) and neurokinin A (NKA)-LI were measured after combined water and acetic acid extraction procedures. Also when measuring cholecystokinin-like immunoreactivity the highest level was obtained following this extraction procedure. RP-HPLC revealed a major component of SP-LI at the position of synthetic SP irrespectively of the extraction method and if the C- or N-terminally directed antiserum was used. Neutral water extracts contained a late eluting component detected with the C-terminally, but not with the N-terminally, directed antiserum. Acid and alkaline extracts, in contrast, contained components which could be detected with the N-terminally, but not with the C-terminally, directed SP-antiserum. Immunoreactive components eluting at the position of NKA and NKB were found in all types of extracts with NKA-, kassinin- and eledoisin-antisera. The NKB- and neuropeptide K (NPK)-components were more prominent in acid than in neutral and alkaline extracts. In conclusion, the present results indicate that rat spinal cord may contain molecular forms of tachykinin-like immunoreactivity in addition to those previously described and illustrate the importance of the choice of extraction method in immunochemical studies. Combined extraction in water and acetic acid appears to be a suitable method when the content of peptides with different chemical properties are to be measured in a tissue sample.

A study of tachykinin-immunoreactivity in the cat visual cortex

The localization of tachykinin-immunoreactivity in the cat visual cortex (area 17) was investigated using immunohistochemical methods. Strong laminar specificity was observed, with immunoreactivity highest in layer V, followed by layers I, VI, II and III, and the lowest density in layer IV. Most of the immunoreactive product was localized in neuronal processes. A few immunopositive cell bodies were also present. The immunopositive neurons were non-pyramidal, multipolar, or bipolar in shape, and mostly found in layer V. There were particularly dense immunopositive fibers and varicosities around somata in layer V. These may represent tachykinin-containing presynaptic terminals (boutons). The results provide anatomical evidence that tachykinins may primarily affect layer V neurons in the cat visual cortex.

Tachykinergic synaptic inputs to neurons of the medial preoptic region which project to the rat arcuate nucleus

Anatomical relationships between tachykinin-containing terminals and neurons of the medial preoptic area that innervate the arcuate nucleus were studied using silver staining of the retrograde tracer wheat germ agglutinin-apoperoxidase-gold (WGA-ApoHRP-gold) complex injected in the arcuate nucleus and pre-embedding immunocytochemistry for neurokinin A (NKA). At the histological level, retrogradely labeled cells not stained for NKA were seen to be surrounded by numerous NKA-immunopositive punctate profiles, in particular in the dorsal part of the medial preoptic area. At the ultrastructural level, retrogradely labeled cell bodies and dendritic profiles displayed highly electron-dense silver particle accumulations over the cytoplasm. The were seen in synaptic contact with one or several NKA-immunoreactive axon terminals containing small clear vesicles and dense-cored vesicles. Such synapses were either symmetrical or asymmetrical. The occurrence of synaptic contacts between tachykinin terminals and cells innervating the arcuate nucleus in the medial preoptic region provides a morphological support for a tachykinergic regulation of preoptic afferences to the arcuate nucleus. These results suggest that tachykinins are implicated in the indirect control of neuronal activity in the arcuate nucleus notably via the preoptic area. Consequently, tachykinins are potentially able to regulate indirectly numerous neuroendocrine events involving the tuberoinfundibular system.

Locustatachykinin immunoreactivity in the blowfly central nervous system and intestine

An antiserum raised against locustatachykinin I, one of four myotropic peptides that have been isolated from the locust brain and corpora cardiaca, was characterized by enzyme-linked immunosorbent assay (ELISA) and used for immunocytochemical detection of neurons and endocrine cells in the nervous system and intestine of the blowfly Calliphora vomitoria. The ELISA characterization indicated that the antiserum recognizes the common C-terminus sequence of the locustatachykinins I-III. Hence, the cross reaction with locustatachykinin IV is less, and in competitive ELISAs no cross reaction was detected with a series of vertebrate tachykinins tested. It was also shown that the antiserum recognized material in extracts of blowfly heads, as measured in ELISA. In high-performance liquid chromatography the extracted locustatachykinin-like immunoreactive (LomTK-LI) material eluted in two different ranges. A fairly large number of LomTK-LI neurons was detected in the blowfly brain and thoracicoabdominal ganglion. A total of about 160 LomTK-LI neurons was seen in the proto-, deuto-, and tritocerebrum and subesophageal ganglion. Immunoreactive processes from these neurons could be traced in many neuropil regions of the brain: superior and dorsomedian protocerebrum, optic tubercle, fan-shaped body and ventral bodies of the central complex, all the glomeruli of the antennal lobes, and tritocerebral and subesophageal neuropil. No immunoreactivity was seen in the mushroom bodies or the optic lobes. In the fused thoracicoabdominal ganglion, 46 LomTK-LI neurons could be resolved. The less evolved larval nervous system was also investigated to obtain additional information on the morphology and projections of immunoreactive neurons. In neither the larval nor the adult nervous systems could we identify any efferent or afferent immunoreactive axons or neurosecretory cells. The widespread distribution of LomTK-LI material in interneurons suggests an important role of the native peptide(s) as a neurotransmitter or neuromodulator within the central nervous system. Additionally a regulatory function in the intestine is indicated by the presence of immunoreactivity in endocrine cells of the midgut.

Bradykinin-induced airway inflammation. Contribution of sensory neuropeptides differs according to airway site

We examined the mechanisms of bradykinin-induced airway microvascular leakage in guinea pig airways by measuring extravasation of Evans blue dye. Animals were pretreated with propranolol (1 mg/kg, intravenous) and atropine (1 mg/kg, intravenous) to block the beta-adrenergic and muscarinic responses, respectively. Bradykinin (250 nmol) instillation into airways significantly increased the leakage of dye in the trachea, main bronchi, and intrapulmonary airways to the same degree. The bradykinin B2-receptor antagonist HOE140 (500 nmol/kg, intravenous) did not alter basal leakage but almost completely inhibited bradykinin-mediated leakage. By contrast, the neurokinin NK1 antagonist FK888 (10 mg/kg, intravenous) partially inhibited bradykinin-induced leakage in trachea (p < 0.01) and main bronchi (p < 0.01), but had no significant effect on intrapulmonary airways. Indomethacin (5 mg/kg, intravenous) had no effect on the plasma leakage after instilled bradykinin. We concluded that the airway inflammatory response to bradykinin administered directly into the airways is mediated by bradykinin B2 receptors and partially mediated by tachykinin release from sensory nerve terminals, whereas cyclooxygenase products have no important role in the response. In the central airways, the contribution of sensory neuropeptides to the bradykinin response is greater than that caused by direct stimulation of the B2 receptor on the endothelium at the postcapillary venule of the bronchial circulation. In contrast, in the peripheral airways, the contribution of direct B2-receptor stimulation on the airway vasculature is greater than that involving sensory neuropeptides.

Calretinin-immunoreactivity in trigeminal neurons innervating the nasal mucosa of the rat

Trigeminal primary neuronal cell bodies were labeled by retrograde transport of Fluoro-gold (FG) from the nasal mucosa of rats. The trigeminal ganglion containing the labeled cell bodies were processed for double stain for calretinin- and tachykinin-immunoreactivities (CR- and TK-irs). Except for a few contralateral cells, all the cells that innervated the nasal mucosa (NM cells) were confined to the ophthalmo-maxillary division of the trigeminal ganglion ipsilateral to the FG application. In the dorsal two-thirds of the ganglion, NM cells formed a cluster in the rostromedial part of ophthalmo-maxillary division (the rostromedial cluster). In the ventral third, the number of cells in the rostromedial cluster markedly decreased. Instead, numerous NM cells were found in the caudolateral part of the ophthalmo-maxillary division (the caudoventrolateral cluster). CR- and TK-irs were detected in 18% and 54% of overall population of NM cells, respectively. Virtually all of CR-immunoreactive (-ir) NM cells coexpressed TK. Although the proportion of TK-ir cells, irrespective of CR-ir, was similar for both clusters, CR-ir cells were more frequent in the caudoventrolateral cluster than in the rostromedial cluster. In the dorsal 1/3 of the ganglion where all the NM cells belonged to the rostromedial cluster, only 8.4% exhibited CR-ir. On the other hand, as much as 30.1% of NM cells expressed CR-ir in the ventral 1/3 where most NM cells were found in the caudoventrolateral cluster. Trigeminal cell bodies innervating the cornea and conjunctivum were located in the rostromedial part of the ophthalmo-maxillary division.(ABSTRACT TRUNCATED AT 250 WORDS)

Insect myotropic peptides: differential distribution of locustatachykinin- and leucokinin-like immunoreactive neurons in the locust brain

Locustatachykinin I is one of four closely related myotropic neuropeptides isolated from brain and corpora-cardiaca complexes of the locust Locusta migratoria. Antiserum was raised against locustatachykinin I for use in immunocytochemistry. It was found that the antiserum recognizes also locustatachykinin II and hence probably also the other two locustatachykinins due to their similarities in primary structure. Locustatachykinin-like immunoreactive (LomTK-LI) neurons were mapped in the brain of the locust, L. migratoria. A total of approximately 800 LomTK-LI neurons were found with cell bodies distributed in the proto-, deuto- and tritocerebrum, in the optic lobes and in the frontal ganglion. Processes of these neurons innervate most of the synaptic neuropils of the brain and optic lobes, as well as the frontal ganglion and hypocerebral ganglion. The widespread distribution of LomTK-LI neurons in the locust brain indicates an important role of the locustatachykinins in signal transfer or regulation thereof. As a comparison neurons were mapped with an antiserum against the cockroach myotropic peptide leucokinin I. This antiserum, which probably recognizes the native peptide locustakinin, labels a population of about 140 neurons distinct from the LomTK-LI neurons (no colocalized immunoreactivity). These neurons have cell bodies that are distributed in the proto- and tritocerebrum and in the optic lobe. The processes of the leucokinin-like immunoreactive (LK-LI) neurons do not invade as large areas in neuropil as the LomTK-LI neurons do and some neuropils, e.g. the mushroom bodies, totally lack innervation by LK-LI fibers. In some regions, however, the processes of the LomTK-LI and LK-LI neurons are superimposed: most notably in the central body and optic lobes. A functional relation between the two types of neuropeptide in the locust brain can, however, not be inferred from the present findings.

Androgen concentration by a sexually dimorphic population of tachykinin-immunoreactive neurons in the rat ventral premammillary nucleus

Strong connections with sexually dimorphic nuclei suggest that the ventral premammillary nucleus (PMv) may be involved in the mediation of reproductive behavior. Steroid autoradiography and immunohistochemistry were used to show that: (1) there is a sex difference in the numbers of PMv neurons that contain tachykinin peptides, (ii) dihydrotestosterone concentrating cells are densely distribution in the PMv and about a quarter of these also contain immunoreactive tachykinin and, (iii) size of the immunoreactive tachykinin population does not respond to alterations in levels of gonadal steroids in adulthood. Thus the PMv appears to make a contribution to the regulation of sexual behavior through androgen-concentrating, tachykinin-containing pathways that are anatomically distinct from estrogen receptive circuitry.

Activation of human neutrophils by tachykinins: effect on formyl-methionyl-leucyl-phenylalanine- and platelet-activating factor-stimulated superoxide anion production and antibody-dependent cell-mediated cytotoxicity

This study examines the contribution of tachykinins to the processes of inflammation. Neurokinin A (NKA), neurokinin B (NKB) and eledoisin (E) but not kassinin (K) have similar effects to substance P (SP) in priming neutrophils for increased superoxide anion (O2-) production in response to formyl-methionyl-leucyl-phenylalanine (FMLP). This similarity in activity may be due to the carboxy amino acid terminal end of these tachykinins being highly conserved. This was confirmed by demonstrating that SP fragment 7-11 (SP7-11) had the same priming effect as the whole molecule, whereas, the amino end fragment 1-4 (SP1-4) inhibited the response to FMLP. The priming effect of tachykinins was not confined to a single stimulus, such as FMLP, since NKA, NKB and SP also enhanced O2- production stimulated by platelet-activating factor (PAF), an important mediator of inflammation but a weak stimulus of O2- production on its own. In addition, all the tachykinins studied increased neutrophil antibody-dependent cell-mediated cytotoxicity (ADCC) towards opsonized target cells. In contrast to their effects on FMLP-induced O2- production, both SP fragments, SP1-4 and SP7-11, stimulated neutrophil ADCC and had a synergistic effect when used together.

Mass spectrometric analysis of opioid and tachykinin neuropeptides in non-secreting and ACTH-secreting human pituitary adenomas

In a study to test the hypothesis that defects in the metabolism of neuropeptides might be a contributing factor to human anterior pituitary tumor formation, the proenkephalin A, proopiomelanocortin (POMC), and tachykinin systems, which produce methionine enkephalin (ME), beta-endorphin (BE), and substance P (SP), respectively, were measured in patients who had a wide variety of pituitary tumors. Mass spectrometry was used to optimize the level of molecular specificity of the ME and BE analytical measurements, and radioimmunoassay was used to measure SP-like immunoreactivity (SP-li). Compared to data obtained from pituitaries from post-mortem controls, the non-secreting tumors contained a significantly lower amount of the POMC neuropeptide, BE. The lower ME level was not significant. However, two adrenocorticotrophic hormone (ACTH)-secreting tumors contained ME, BE, and SP-li amounts that were much higher than both the controls and nonsecreting tumors. These data suggest that a hypometabolism of the POMC precursor may be operating in non-secreting tumors, and that a hypermetabolism of the proenkephalin A, POMC, and tachykinin precursors may be operating in two ACTH-secreting tumors. These data demonstrate that mass spectrometry plays a critical role in the study of human pituitary tumors.

Immunochemical characterisation of tachykinin immunoreactivity in the nervous system of the garden snail, Helix aspersa

1. Circumoesophageal ganglia and foot muscle of the garden snail, Helix aspersa, were subjected to immunocytochemistry using antisera to the tachykinins, substance P (SP), neurokinin A (NKA), kassinin (KAS) and eledoisin (ELE). 2. Immunoreactivity in neuronal somata and fibres was detected only with the SP antiserum. 3. SP and NKA radioimmunoassays were performed on extracts of circumoesophageal ganglia. In common with immunocytochemistry, immunoreactivity was only detected with the SP antiserum. 4. Gel permeation chromatography of extracts resolved a single peak of immunoreactivity eluting slightly later than synthetic mammalian SP. Reverse-phase HPLC of immunoreactive fractions resolved two immunoreactive peptides representing oxidised and reduced forms of a single peptide. 5. These data suggest that the nervous system of H. aspersa contains a single tachykinin with C-terminal structural characteristics similar to mammalian SP.

Insect tachykinin-like peptide: distribution of leucokinin immunoreactive neurons in the cockroach and blowfly brains

Antisera were raised against leucokinin I, a cockroach myotropic neuropeptide with some resemblance to vertebrate tachykinins. These antisera were used for immunocytochemical mapping of neurons and neurosecretory cells in the brains of a cockroach and a blowfly species. The leucokinin immunoreactive cells are distinct from neurons that can be labeled with antisera against vertebrate type tachykinins. It is suggested that leucokinin-like peptides may have roles as neurohormones and neuromodulators in the insect nervous system.

Modulation of the immune response by tachykinins

Neuro-immunology is becoming an increasingly important discipline of immunology. This review has examined the immunomodulatory function of one group of neuropeptides, the TK, particularly SP and NKA. These peptides are localized in primary afferent nerves which have been shown to innervate several immune organs. In addition, binding sites for the TK have been demonstrated in thymus, spleen and lymph node. Several immune cell types also express neurokinin receptors including human circulating lymphocytes with binding to the Th/i class predominating, murine T and B cells, a human T lymphoblastoid cell line, human monocytes, rabbit polymorphonuclear leucocytes and guinea-pig macrophages. The apposition of nerves with immune cells and receptors for neuropeptides thus produces an environment for interaction between the nervous and immune systems. Studies in vitro and, more recently, in vivo have examined how the TK regulate immune cell responses. The TK stimulate proliferation of T cells, enhance mitogen-induced release of cytokines including IFN-gamma, TNF-alpha, IL-1 and IL-6 from mononuclear cells and macrophages, enhance immunoglobulin secretion and affect cellular chemotaxis and phagocytosis. Studies in vivo have shown a role for TK in lymphocyte recirculation of sheep lymph nodes, reversal of stress-induced thymic involution and Ig production in both rat and mouse. Many of these effects appear to be mediated via NK-2 type receptors. To date, most of the work has involved studies in vitro, but the results from these are now being validated by studies in vivo where both the immune system and neuropeptides are able to interact at many anatomical sites. The complexities of the immune and the nervous systems mean that only a small number of potential interactions has been examined. Future studies can be expected to amplify these observations, especially with respect to the understanding of inflammatory and immune diseases in humans.

Light microscopic immunoenzyme and electron microscopic immunogold cytochemistry reveal tachykinin immunoreactivity in Merkel cells of pig skin

Light microscopic (LM) immunoenzyme and electron microscopic (EM) immunogold cytochemistry were used to demonstrate the presence and subcellular distribution of tachykinin (substance P)-like immunoreactivity in Merkel cells of pig skin. Merkel cells of sinus hair follicles were strongly immunoreactive for tachykinins. In contrast, tachykinin-like immunoreactivity was absent from or very weak in epidermal Merkel cells while subepidermal and some intraepidermal nerve fibres were clearly immunopositive for tachykinins. Postembedding immunogold cytochemistry on the EM level revealed that tachykinin-like immunoreactivity was confined to the secretory granules in Merkel cells. Tachykinin immunoreactivity was clearly absent from the axon of the Merkel cell-axon complex. The selective presence of tachykinin immunoreactivity in secretory granules strongly suggests that tachykinins are synthesized in cutaneous Merkel cells, at least of pig. This is a further indication for the concept that the Merkel cell is a member of the diffuse neuroendocrine system. However, the functional role of tachykinins like substance P and neurokinin A and of other peptides present in Merkel cells remains enigmatic.

Tachykinin and calcitonin gene-related peptide immunoreactivities and mRNAs in the mammalian enteric nervous system and sensory ganglia

Tachykinins and CGRP label two distinct populations of neurons innervating the digestive system: intrinsic and extrinsic, afferents. The bulk of SP/tachykinin innervation originates from intrinsic neurons, even though a minor component of this innervation derives from afferent neurons, which are mostly located in dorsal root ganglia. Afferent SP/tachykinin fibers are mainly confined to a perivascular location and to the submocosa in the gut, but are distributed also to the hepatobiliary pathway and pancreas. On the contrary, the extrinsic CGRP-containing afferents form a major component of the sensory innervation of the alimentary tract, including the rich CGRP innervation of the esophagus, stomach, hepatobiliary tract, pancreas, and vasculature, as well as a portion of non-vascular fibers distributed to the intestinal wall. Tachykinin and CGRP immunoreactivities appear to be colocalized in a population of nerve fibers, which are likely to be extrinsic, afferent, since colocalization of these peptide immunoreactivities has not been reported in intrinsic neurons. The presence of SP/NKA-encoding transcripts in the enteric nervous system and sensory ganglia and the lack of hybridization signal with RNA probes complementary to NKB mRNA indicate that the PPT I gene, but not the PPT II gene, is transcribed in these structures. This observation, along with receptor binding sites and radioimmunoassay data, which have failed to detect NKB receptor binding sites or immunoreactivity (Eysselein et al., 1990; Maggio, 1988; Mantyh et al., 1988; 1989) in the intestine of several mammals, is consistent with a differential expression of the two PPT genes in the periphery and in the central nervous system (Brecha et al., 1989; Warden and Young, 1988). A differential expression of the tachykinin-encoding genes, the existence of multiple tachykinin receptor subtypes (Mantyh et al., 1988; 1989), and the findings that tachykinins can be differentiated on the basis of the potency of their activities (Galligan et al., 1987; Maggio, 1988), support the possibility that each tachykinin is expressed in separate, and perhaps functionally distinct neuronal systems. alpha- and beta-CGRP genes also are differentially expressed according to the neuronal populations: alpha-CGRP mRNA is the most prominent form in sensory ganglia, and beta-CGRP mRNA is the only form detected in enteric neurons (Mulderry et al., 1988; Sternini and Anderson, 1990). In addition, distinct distributions of mRNAs generated from the two CGRP genes have been reported in the central nervous system (Amara et al., 1985). The differential expression patterns of alpha- and beta-CGRP mRNAs are consistent with a differential regulation of the alpha- and beta-CGRP genes.(ABSTRACT TRUNCATED AT 400 WORDS)

A microcolumnar structure of monkey cerebral cortex revealed by immunocytochemical studies of double bouquet cell axons

Immunocytochemical methods were used to study 28,000 mol. wt calbindin and tachykinin immunoreactivity in the monkey cerebral cortex. Calbindin and tachykinin immunoreactivity give rise to a generally different pattern of staining of cell bodies and terminal-like puncta. However, the staining of long, vertically-oriented bundles of processes--identical to classical double bouquet cell axonal arborizations--is the most prominent feature of the pattern of both calbindin- and tachykinin-immunoreactive staining. These bundles form a widespread and regular columnar system descending from layer II to layers III-V. The bundles are most evident in layer III where, in tangential sections, they have a density of 7-15 bundles/10,000 microns 2 with a center-to-center spacing of 15-30 microns. The distribution of immunoreactive bundles through the cortex is not homogeneous; somatic sensory, auditory, and visual areas display a large number of calbindin-immunoreactive bundles while tachykinin-immunoreactive bundles are only numerous in the auditory areas and in area 18 of the visual cortex. In the motor cortex (area 4) few or no immunoreactive bundles are visualized with either antibody. Correlative light and electron microscope analysis of tachykinin immunoreactive bundles in the primary auditory cortex shows that the tachykinin-positive axons of the bundles form symmetrical synaptic contacts with dendritic shafts (57%) and spines (43%). Frequently, several immunoreactive boutons that arise from the same fiber are seen climbing along the surfaces of vertically-oriented, non-immunoreactive processes which include myelinated and unmyelinated axons and probably glial processes. The same ultrastructural features and a similar synaptic distribution were found in a previous study [DeFelipe et al. (1989) Brain Res. 503, 49-54] of calbindin-positive bundles in the somatic sensory cortex (areas 3a and 1). Despite the virtually identical morphological features of tachykinin- and calbindin-immunoreactive bundles, colocalization studies demonstrate little coexistence of the two antigens in somata and none in the axonal bundles of double bouquet cells. These data suggest that the double bouquet cell is a chemically heterogeneous, but ubiquitous morphological type of cortical interneuron, whose uniquely bundled axonal system, which is probably GABAergic, imposes a fundamental microcolumnar organization upon the cerebral cortex.

Identification of immunoreactive neuropeptide-gamma in human placenta: localization, secretion, and binding sites

The aim of the present study was to evaluate the possible presence of immunoreactive neuropeptide-gamma (irNPY) in human placenta. Acidic extracts of human placental tissue collected at term pregnancy contained high irNPY concentrations. The extracted irNPY eluted from HPLC with the same retention time as synthetic NPY. The presence of the peptide in placental cells was confirmed by immunohistochemical findings showing numerous cells of the cytotrophoblast layer positively staining for NPY. Further supporting local production of the peptide, primary cultures of human placental cells released irNPY into the culture medium and the addition of high K+ concentrations increased the release of the peptide. The finding of irNPY in human placenta stimulated the characterization of binding sites of NPY in the same tissue. Using autoradiographic techniques we showed specific binding of [125I]NPY in human placental tissue. The binding of [125I]NPY to the placental receptors was saturable and widely distributed within the placental tissue. Finally, the addition of NPY to the medium of cultured placental cells increased the release of immunoreactive CRF, suggesting a possible role of NPY in placental hormone production. The effect of NPY was dose related and augmented by the addition of norepinephrine (10 nM). These results showed that human placenta produces and secretes irNPY and that NPY receptors are present in placental tissue. Moreover, the evidence that NPY stimulated the release of immunoreactive CRF from cultured placental cells suggests an action of NPY in placental hormonogenesis.

Reduced numbers of calcitonin gene-related peptide-(CGRP-) and tachykinin-immunoreactive sensory neurones associated with greater enkephalin immunoreactivity in the dorsal horn of a mutant rat with hereditary sensory neuropathy

The mutilated foot rat is a mutant with autosomal recessive sensory neuropathy and frequent mutilation of the hindlimbs. Decreased numbers of dorsal root ganglion cells and diminished sensitivity to painful stimuli are characteristics of these animals. By use of immunocytochemistry, changes in the distributions of peptides involved in sensory and/or autonomic regulation, i.e., calcitonin gene-related peptide (CGRP), tachykinins, enkephalin and neuropeptide Y in spinal cord, dorsal root ganglia and skin of these animals, were studied. In comparison with normal litter-mate controls, the dorsal horn of mutilated foot rats contained substantially fewer CGRP- and tachykinin-immunoreactive fibres but more fibres immunoreactive for enkephalin. Many enkephalin-immunoreactive cell bodies were also found in the dorsal horn of the mutants, by contrast none were visible in control animals. Neuropeptide Y immunoreactivity was, however, unchanged in the spinal cord of the mutants. In the dorsal root ganglia of the mutants, the number of CGRP- or tachykinin-immunoreactive cells and their proportion to total neuronal numbers were significantly less in comparison with normal controls. The diameter range of CGRP- and tachykinin-immunoreactive cells shifted from small (15-25 microns) to medium size (25-45 microns) as revealed by frequency distribution histograms. The skin from the affected fore- and hindlimbs of the mutant rats, in keeping with fewer CGRP- and tachykinin-immunoreactive cells in the dorsal root ganglia, contained substantially less fibres immunoreactive for CGRP and tachykinins; a difference that was not seen in skin of unaffected areas (whiskers and snout). By contrast, neuropeptide Y-immunoreactive fibres showed a normal distribution around blood vessels and sweat glands of mutilated foot rats. The data suggest that diminished pain perception in the mutilated foot rat is related to loss of peptide-containing sensory neurones. Furthermore, the intraspinal increase of enkephalinergic neurons in the dorsal horn, concomitant with the decreased number of primary sensory neurones, may also play a contributory rôle in reducing pain thresholds.