Neurokinin A is the predominant tachykinin in human bronchoalveolar lavage fluid in normal and asthmatic subjects

BACKGROUND

Multiple sensory neuropeptides are present in human airways and may contribute to diseases such as asthma. This study quantified and characterised substance P (SP), neurokinin A (NKA), and calcitonin gene related peptide (CGRP) immunoreactivity in bronchoalveolar lavage fluid in asthmatic and normal subjects.

METHODS

Using specific radioimmunoassay (RIA), SP, NKA and CGRP were measured in bronchoalveolar lavage fluid from asthmatic subjects (n = 5), normal subjects (n = 5), atopic non-asthmatic subjects (n = 6), and asthmatic subjects four hours after allergen challenge (n = 12). Peptide immunoreactivity was characterised using high performance liquid chromatography (HPLC) and RIA.

RESULTS

No SP or CGRP immunoreactivity was detected in any of the fractions from samples after extraction, HPLC, and RIA. Non-specific binding resulted in spurious SP immunoreactivity being detected in bronchoalveolar lavage fluid when no extraction process was employed. NKA was detected in significant amounts in asthmatic (median 550, range 425-625 pg/ml) and normal subjects (median 725, range 350-1425 pg/ml). The level of NKA was significantly higher in the asthmatic subjects after allergen challenge (median 750, range 350-1250 pg/ml) than in unchallenged asthmatic subjects (median 600, range 425-600 pg/ml, p < 0.01).

CONCLUSIONS

Extraction and characterisation of peptides from bronchoalveolar lavage fluid must be performed to ensure that the measured immunoreactivity represents target peptide. NKA is present in bronchoalveolar lavage fluid in high concentrations and is the predominant tachykinin. The concentrations of NKA are similar in normal subjects and subjects with mild asthma.

Neuropeptide Y, neurokinin A and neurotensin in brain regions of Fawn Hooded "depressed", Wistar, and Sprague Dawley rats. Effects of electroconvulsive stimuli

1. Concentrations of neuropeptide Y (NPY)-, neurokinin A (NKA)- and neurotensin (NT)-like immunoreactivity (-LI) were measured in brain tissues of Fawn Hooded (FH) (a model of depression), Wistar (W) (control for depression) and Sprague Dawley (SD) rats (control for strain) with the aim to explore possible associations between neuropeptides and models of depression. 2. In addition, peptides were determined after six electroconvulsive stimuli (ECS) or six sham ECS ("baseline") in order to investigate ECS mechanisms of action. 3. Baseline NPY-LI concentrations were markedly lower in the hippocampus of the "depressed" FH compared to the W and SD animals. 4. Baseline NKA-LI concentrations were higher in the occipital cortex and NT-LI concentrations in the occipital cortex, frontal cortex, and hypothalamus of the FH and W compared to the SD rats. 5. ECS increased NPY-LI in the hippocampus, frontal cortex and occipital cortex of all three strains. In the hippocampus, the increase was significantly larger in the FH compared to the W and SD rats. ECS also increased NKA-LI in the hippocampus. 6. In contrast, ECS decreased NT-LI in the occipital cortex of the FH and W animals. 7. The results indicate that NPY may play a role in depression and that changes in NPY and NKA probably constitute one of the mechanisms of ECT action. More speculatively, NT may also be involved in depression.

Increased concentrations of calcitonin gene-related peptide-like immunoreactivity in rat brain and peripheral tissue after ischaemia: correlation to flap survival

The effects of experimentally induced ischaemia after free-flap surgery on concentrations of neuropeptide Y (NPY), neurokinin A (NKA), substance P (SP) and calcitonin gene-related peptide (CGRP)-like immunoreactivity (-LI) were studied in flap tissue and in different regions of the rat brain (striatum, hippocampus, pituitary, hypothalamus, frontal and occipital cortex). Ten days after the operation, CGRP-LI and NKA-LI were decreased in the ischaemic tissue but increased in the surrounding tissue. In the brain, CGRP-LI was increased in five of six regions analysed, with the exception of the striatum. SP-LI and NKA-LI were increased in the pituitary and hippocampus, but decreased in other brain regions. Changes of CGRP-LI in the brain correlated positively with the CGRP-LI concentrations in the surrounding flap tissue and the CGRP-LI concentrations in the ischaemic flap tissue with the extent of flap survival. The results of the present study suggest that higher concentrations of CGRP-LI are related to tissue survival and that endogenous CGRP has a regulatory effect in ischaemia.

Projections and actions of tachykininergic, cholinergic, and serotonergic neurones in the intestine of the atlantic cod

The native tachykinins cod neurokinin A and cod substance P, serotonin and acetylcholine have excitatory effects on the circular smooth muscle of the cod intestine. Furthermore, immunoreactivities to the cod tachykinins, serotonin and two markers for cholinergic neurones, viz. choline acetyltransferase and vesicular acetylcholine transporter, have been demonstrated in myenteric neurones of the cod intestine. In order to elucidate whether the neurones containing these substances project orally and thus might be involved in the ascending excitatory reflex of peristalsis, myotomy operations have been performed on the cod intestine. The immunoreactive areas of the myenteric plexus immediately oral and anal to the myotomy operations have been measured by using confocal laser scanning microscopy. Large accumulations of immunoreactivity to the tachykinins are found on the anal side of the myotomies, indicating oral projections of tachykininergic neurones. The areas immunoreactive to serotonin and choline acetyltransferase are of equal size on the oral and anal sides. Since the tachykinin containing neurones of the intestine project orally, and since cod neurokinin A and cod substance P have excitatory effects on circular smooth muscle, we conclude that tachykininergic neurones are involved in the ascending excitatory reflex of peristalsis in the cod intestine.

Tachykinins in the pineal gland: effect of castration and ganglionectomy

In this investigation, the presence of NKA-immunoreactive substances was determined in pineal glands from intact, castrated and castrated, testosterone-treated male rats. The effect of environmental light, melatonin treatment and superior cervical ganglionectomy on pineal NKA-immunoreactive substances was also investigated. The results obtained show that NKA is present in measurable amounts in the rat pineal, and NPK is probably also present, Orchidectomy was followed by an increase in the content of NKA-immunoreactive substances in the pineal gland. The replacement treatment with testosterone propionate in castrated rats blocked this effect. NKA-immunoreactive substances were not significantly different quantitatively in pineals from rats killed under light or under darkness. The removal of the superior cervical ganglia was followed by a significant increase in the NKA-immunoreactive substance content in the pineal gland of male rats. These results indicate that NKA and other tachykinins are present in the pineal gland of the male rat, and they seem to be regulated by gonadal hormones and the innervation originated from the superior cervical ganglia.

Sensory nerves in the interface membrane of aseptic loose hip prostheses

We studied the presence of sensory nerves by immunohistochemistry in the interface membranes of hip prostheses after aseptic loosening. Substance P (SP), neurokinin A (NKA) and calcitonin gene-related peptide (CGRP) were analysed as was protein gene product (PGP) 9.5, a general marker for nerve fibres. We identified nerve fibres in all samples but differences in their density were found. SP- and NKA-positive fibres were predominantly non-vascular, forming varicose nerve terminals. CGRP-immunoreactive nerve fibres with varicose terminals were seen mostly close to blood vessels, but also as free nerve endings. Sensory neuropeptides participate not only in nociception but also stimulate immune cells to release cytokines. The presence of sensory nerves in the interface membrane may reflect a pathophysiological response contributing to the aseptic loosening of hip prostheses.

Substance P and neurokinin A in gingival crevicular fluid in periodontal health and disease

The aims of the present study were to investigate whether the tachykinins substance P and neurokinin A were present in gingival crevicular fluid in both periodontal health and disease and to study the relationship with periodontal inflammation. Gingival crevicular fluid (GCF) was collected from a healthy, a gingivitis and a periodontitis site in 20 subjects with periodontitis and from a healthy site in 20 subjects without periodontitis. The volume of GCF was measured and each sample subsequently analysed for substance P and neurokinin A by radioimmunoassay. There were significantly increased levels of substance P-like immunoreactivity (SP-LI) and neurokinin A-like immunoreactivity (NKA-LI) in gingivitis and periodontitis sites compared with healthy sites. Both tachykinins were significantly elevated in periodontitis affected subjects, with significantly more tachykinin-like immunoreactivity at healthy sites in periodontitis affected compared with periodontally-healthy subjects. Despite the considerable individual variation in the levels of SP-LI and NKA-LI, both tachykinins were present at levels at which they could have biological activity. It is concluded that substance P and neurokinin A may have a rôle in the pathogenesis of periodontal disease and that further investigations could prove useful in clarifying the mechanisms through which neuropeptides could modulate periodontal health and disease.

Distribution and colocalization of calcitonin gene-related peptide, tachykinins, and vasoactive intestinal peptide in normal and idiopathic unstable human urinary bladder

The distribution of nerves containing calcitonin gene-related peptide (CGRP), substance P (SP), neurokinin A (NKA), and vasoactive intestinal peptide (VIP) was examined in the human urinary bladder, using both single- and double-label immunohistochemistry. Nerves containing CGRP and tachykinins were typically present within the subepithelial region, encircling intramural ganglia and around blood vessels. These nerves were sparsely distributed, and only very rarely projected to the smooth muscle bundles of the detrusor. In contrast, VIP-containing nerves formed a dense subepithelial plexus and also projected to the detrusor muscle bundles. The double-label studies revealed that approximately 26% +/- 10% of CGRP-immunoreactive nerves also contained SP and NKA, but that no CGRP fibers coexpressed VIP. Conversely, all SP-immunoreactive fibers also contained CGRP, and many coexpressed NKA. At least three neurochemically distinct populations of nerves can therefore be discerned in the human bladder: VIP/-, CGRP/-, and CGRP/SP/ +/- NKA. The density of CGRP and SP-immunoreactive nerves within the subepithelium of 14 women with urodynamically-proven idiopathic detrusor instability was increased by 82% (p = 0.003) and 94% (p = 0.036), respectively, relative to that of 14 control women with no symptoms of frequency or urgency. This effect was not due to an increase in overall nerve density, because immunoreactivity for the general nerve marker, protein gene product, was not significantly different between the two groups (p = 0.21). The results indicate that at least some patients with detrusor instability demonstrate increases in a specific class of nerve fibers containing CGRP and SP. These peptides are characteristic of sensory neurons in a number of species, suggesting that abnormalities in the afferent arm of the micturition reflex may be associated with detrusor instability.

Indomethacin influences regulatory peptides and increases DNA synthesis in the gastrointestinal tract of the rat

OBJECTIVE

To examine the effect of long-term administration of indomethacin on regulatory peptides and DNA synthesis.

DESIGN

Sprague-Dawley rats were treated with 1 mg/kg indomethacin subcutaneously or indomethacin and 500 micrograms/kg oral prostaglandin E2 or solvents for 2 months before labelling with methyl-3H-thymidine.

METHODS

The labelling index, growth fraction and the number of epithelial cells were determined on autoradiographs of the stomach small intestine and colon. Plasma and gastrointestinal tissue concentrations of regulatory peptides were analysed by radioimmunoassay.

RESULTS

Indomethacin increased the concentration of somatostatin in the gastric fundus and ileum and reduced it in the colon. Prostaglandin E2 reduced the somatostatin concentration in the duodenum and colon. Indomethacin increased the concentration of neurotensin neurokinin A and glucagon in the distal small intestine and reduced the glucagon level in the colon. Prostaglandin E2 prevented such changes. Indomethacin increased DNA synthesis in the small intestine and produced hypoplasia of the villi. These changes were prevented by prostaglandin E2, except for the villous hypoplasia observed in the distal small intestine. Prostaglandin E2 reduced the labelling index in the antrum and colon.

CONCLUSION

Endogenous prostaglandins selectively modulate the synthesis and/or release of regulatory peptides and regulate the outflow of cells from the epithelial surface. Indomethacin induces hypoplasia, which triggers a secondary trophic reaction in the epithelium that may, at least partially, be mediated by regulatory peptides.

[The simultaneous analysis of substance P, somatostatin, neurokinin and neurotensin by capillary zone electrophoresis]

Neuropeptides play an important part in several different areas of neurochemistry. Recently, capillary electrophoresis (CE) was developed for analysis of neuropeptides. This paper reports a capillary zone electrophoretic method for the simultaneous separation and quantitative determination of the substance P (SP), somatostatin (SS), neurokinin (NKA) and neurotensin (NT). The separation was performed on a 50microm x 60cm fused-silica capillary using 0.1mol/L at pH 2.7 phosphate as buffer. The eluted fractions were detected at 214nm.

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.

Identification of bradykinin, substance P, and neurokinin A in human dental pulp

Methodology was developed that uses reverse phase, high performance liquid chromatography (HPLC) to identify and quantify bradykinin, substance P, and neurokinin A contained in dental pulp tissue. Pulp tissue was prepared and homogenized from teeth frozen in liquid nitrogen, Known amounts of three substances found in inflamed tissue were added to the homogenized tissue and also to bovine serum albumin (BSA) (positive control), and supernatants were analyzed using HPLC. Other pulp tissue was prepared and analyzed without the addition of the substances. Recovery from the pulp and BSA with added substances was similar, with bradykinin recovered maximally. In pulp tissue without additions, all three substances were recovered. Thus HPLC appears to be a viable alternative to other methods for identification of these substances and allows for their quantification.

An immunohistochemical screening of neurochemical markers in fungiform papillae and taste buds of the anterior rat tongue

The occurrence and distribution of several neurochemical markers were investigated. Numerous nerve fibres were shown, using antibodies to protein gene product (PGP) 9.5, neurone-specific enolase, calcitonin gene-related peptide (CGRP), substance P. neurokinin A or protein S-100. The presence of vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine amide (PHI), neuropeptide tyrosine, dopamine-beta-hydroxylase (DBH), cholecystokinin/gastrin, glutamate and galanin was more scarce. Nerve fibres containing these above-mentioned markers were found at several locations, i.e. in the epithelium, connective tissue, and around blood vessels. In the taste buds, numerous PGP 9.5, neurone-specific enolase-, CGRP-, substance P-, neurokinin A- and protein S-100-containing structures were found, but few VIP and galanin ones. No immunoreactivity was found with antibodies against somatostatin, bombesin, enkephalin or dynorphin. These findings extend knowledge about the general as well as the neurochemical messenger-based innervation of rat fungiform papillae, forming a firm basis for future functional investigations of normal, experimental and also clinical materials.

Neuropeptides in the saliva of healthy subjects

Five neuropeptides: Substance P (SP), Neurokinin A (NKA), Calcitonin Gene-Related Peptide (CGRP), Neuropeptide Y (NPY) and Vasoactive Intestinal Polypeptide (VIP), were measured in the saliva of eight subjects. The saliva was collected using different stimulation techniques: whole resting saliva, whole paraffin stimulated saliva, whole citric acid stimulated saliva and parotid saliva of different secretion rates -0.25 mL/min, 0.50 mL/min and 1.00 mL/min, also stimulated by citric acid. The neuropeptides were analysed by radioimmunoassay. The results showed that the concentration of all neuropeptides decreased significantly, two- to four-fold (CGRP up to 16-fold) in whole saliva, when the salivary secretion rates increased six- to eight-fold due to stimulation. However, the amounts of all neuropeptides released over time into the whole saliva increased two- to five-fold (ten-fold for CGRP) as the volumes of saliva increased due to chewing-stimulation as compared to resting saliva or citric acid stimulated saliva. There was also more CGRP in the resting saliva than in the citric acid stimulated saliva. The concentration of CGRP in the parotid saliva decreased three- to ten-fold when the salivary flow increased, whereas the concentration of NKA increased three- to four-fold and that of NPY almost two-fold under the same conditions. The concentrations of SP and VIP did not change in the different flows of parotid saliva. The release of all neuropeptides in the parotid saliva over time showed significant increases (3-14-fold) when the secretion rates increased except CGRP, which showed no changes at all. We concluded that neuropeptides are continuously released into the saliva. Their amounts increase with stimulation, but they are diluted by the increased volume of saliva, and they are also affected by the mode of stimulation-muscular activity leads to a greater release than citric acid stimulation. As the neuropeptides play an important role in the control of salivary secretory mechanisms, their normal occurrence and release are of fundamental importance for the understanding of the function of the salivary glands.

Immunocytochemical characterization of malignant schwannoma-derived cells in culture

We recently demonstrated that cultured malignant schwannoma (MS)-derived cells can support human skin mast cell (HSMC) survival in vitro. Cultured HSMCs were spindleshaped in close contract with MS-derived cells, suggesting cell to cell interaction. To elucidate the mechanism of the enhanced HSMC survival in coculture with MS-derived cells and the cellular interactions between HSMC and MS-derived cells, we examined the immunocytochemical characteristics of MS-derived cells using immunofluorescence. Morphologically, cultured MS-derived cells were polygonal with abundant cytoplasm and resembled perineurial cells. The cultured cells immunoreacted positively with vimentin, fibronectin, laminin and collagen IV, but negatively with anti-S100 protein, anti-neuron specific enolase, and anti-neurofilament (68 kd, 145 kd, 200 kd) antibodies. MS-derived cells were distinct from Schwann cells in their lack of S100 protein and also distinguishable from endoneurial fibroblasts that produce fibronectin, but never expressed laminin or collagen IV. MS-derived cells thus possess the characteristics of perineurial cells in their general morphology and their immunocytochemical properties. Immunoreactivity for substance P (SP) and neurokinin A (NKA) was found in the cytoplasm of these cells, particularly around the nuclei. Vasoactive intestinal peptide, somatostatin, and calcitonin gene related peptide were negative. From these findings, we characterized the MS-derived cell's in vitro properties and concluded that it is similar to a perineurial cell. The extracellular matrix protein, laminin, and fibronectin expressed in the MS-derived cell might contribute to HSMC survival and morphology through cell to matrix adhesion. Neuropeptides such as SP and NKA, expressed in the MS-derived cell, might play some role in enhanced HSMC survival in vitro.

Microtopography of the autonomic nerves in the rat knee: a fluorescence microscopic study

BACKGROUND

The autonomic innervation of the joint is involved in different functions, such as sensory inputs, modulation of the function of immune cells, and trophic actions. To have a basis for further studies of the arthritic knee joint we have investigated the topographical distribution of different neuropeptides in knees of newborn and adult rats and in adult rats after arthritis induction.

METHODS

The distribution of the neuropeptides calcitonin gene-related peptide (CGRP), neurokinin A (NKA), substance P (SP), and neuropeptide Y (NPY) was analyzed using fluorescence immunohistochemistry. Samples were investigated after fixation by perfusion and decalcification by a special method which allows studies in bone tissue. Vascular structures were analyzed by scanning electron microscopy (SEM) of vascular resin casts.

RESULTS

In all tissues of the joint (synovial membrane, vessels, fibrous structures, bone, and cartilagineous tissues) CGRP and NKA are the most frequent neuropeptides. They are localized in free or perivascular fibers predominantly around arteries and arterioles. The NPY-ergic perivascular fibers even enter the vessel wall. Generally, SP-ergic fibers occur rarely. Free NKA- and CGRP-ergic nerve fibers spread out in the synovial lining layer reaching the synovial cavity and the outer layers of the articular and metaphyseal cartilage. In the cartilagineous tissue these nerves contact the chondrocytes. The density of NKA- and CGRP-immunoreactive fibers is lower in newborn rats than in adult rats. Six hours after arthritis induction SP-, NKA-, and CGRP-immunoreactivity is enhanced especially in perivascular fibers. The related vessels are dilated substantially.

CONCLUSIONS

The distribution pattern of the autonomic nerves found in this study might reflect the functions of these nerves: control of the microcirculation, sensory and even trophic functions. The new finding of CGRP- and NKA-ergic fibers in the outer layer of the cartilage can also have implications for the pathogenesis of rheumatoid arthritis.

Induction of tachykinin gene and peptide expression in guinea pig nodose primary afferent neurons by allergic airway inflammation

Substance P (SP), neurokinin A (NKA), and calcitonin gene-related peptide (CGRP) have potent proinflammatory effects in the airways. They are released from sensory nerve endings originating in jugular and dorsal root ganglia. However, the major sensory supply to the airways originates from the nodose ganglion. In this study, we evaluated changes in neuropeptide biosynthesis in the sensory airway innervation of ovalbumin-sensitized and -challenged guinea pigs at the mRNA and peptide level. In the airways, a three- to fourfold increase of SP, NKA, and CGRP, was seen 24 h following allergen challenge. Whereas no evidence of local tachykinin biosynthesis was found 12 h after challenge, increased levels of preprotachykinin (PPT)-A mRNA (encoding SP and NKA) were found in nodose ganglia. Quantitative in situ hybridization indicated that this increase could be accounted for by de novo induction of PPT-A mRNA in nodose ganglion neurons. Quantitative immunohistochemistry showed that 24 h after challenge, the number of tachykinin-immunoreactive nodose ganglion neurons had increased by 25%. Their projection to the airways was shown. Changes in other sensory ganglia innervating the airways were not evident. These findings suggest that an induction of sensory neuropeptides in nodose ganglion neurons is crucially involved in the increase of airway hyperreactivity in the late response to allergen challenge.

In vivo exposure to nitrogen dioxide (NO2) induces a decrease in calcitonin gene-related peptide (CGRP) and tachykinin immunoreactivity in guinea-pig peripheral airways

The mammalian respiratory tract is densely innervated by sensory and autonomic fibres. Subsets of the nerves contain bioactive regulatory peptides, such as substance P, calcitonin gene-related peptide (CGRP), and neurokinins. The sensory nervous system responds to inhaled irritants, resulting in a release of neuropeptides and, thus, a decrease in the peptide immunoreactivity of the fibres. We examined the effects of inhaled nitrogen dioxide (NO2), a well-known indoor and outdoor air pollutant, on pulmonary sensory neuropeptides. Guinea-pigs were exposed for 4 h to 18 parts per million (ppm) NO2 or to air (n = 5 each). At the end of the exposure, they were killed with urethane and their lungs were fixed in 1% paraformaldehyde in phosphate-buffered saline. Cryostat sections were stained with antisera to an anatomical nerve marker, protein gene product (PGP) 9.5, and to CGRP and tachykinins, utilizing the avidin-biotinylated peroxidase method. In the noncartilaginous airways (diameter < 250 microns) of NO2-exposed animals, less tachykinin- and CGRP-immunoreactive nerve fibres were found compared with controls. No change was seen in the total nerve fibre distribution (PGP 9.5). It is concluded that the peptidergic nerves of guinea-pig peripheral airways are a sensitive indicator of exposure to nitrogen dioxide.

Two different approaches for developing immunometric assays of haptens

To improve immunoassays of small haptens, we developed two different approaches for their measurement in a non-competitive format. We first devised two-site immunometric assays for small peptides (8-11 amino acids) by selecting two sets of antibodies specifically directed against C- and N-terminal moieties of the peptides. In each case, assay sensitivity improved substantially over that of the corresponding competitive assays. More interestingly, all of these new immunometric assays were much more specific than the competitive assays. In a second approach, we developed a new procedure, solid-phase-immobilized epitope immunoassay (SPIE-IA), in which a single monoclonal antibody uses the same epitope for capture and tracer binding and the hapten is covalently cross-linked to solid-phase proteins. To date, SPIE-IA have been successfully applied to the determination of haptens bearing primary amino groups, including substance P, thyroxine, leukotriene C4, endothelin, and angiotensin II. In each case, assay sensitivity was significantly improved.

Effects of adjuvant on neuropeptide-like immunoreactivity in experimentally induced temporomandibular arthritis in rats

Substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivities (-LI) were examined in cerebrospinal fluid (CSF), plasma and temporomandibular joint (TMJ) perfusates in rats 1 and 12 h after inoculation at the base of the tail (0.05 ml) or injection into the right TMJ (0.01 ml) of heat-killed Mycobacterium butyricum in paraffin oil. In the rats inoculated at the base of the tail (polyarthritic rats), there was a significant increase of CGRP-LI and NKA-LI. The changes in neuropeptide-LI were not as marked in the CSF of rats injected with adjuvant in one TMJ (monoarthritic rats) as in the polyarthritic group. Instead, the most significant changes in the monoarthritic rats were seen in the perfusates of both TMJs. The increases in SP-, NKA-, CGRP- and NPY-LI were significant for both TMJs and more pronounced than in the polyarthritic rats. The results show that inoculation of adjuvant at the base of the tail induces significant changes of neuropeptide-LI predominantly in CSF, whilst an intra-articular injection induces bilateral changes in neuropeptide-LI in joint perfusate. Therefore, two different neural mechanisms may be involved early in adjuvant-induced poly- and monoarthritis.

Neurochemical markers of human fungiform papillae and taste buds

The presence of distribution of several neurochemical markers in human fungiform papillae and taste buds were investigated by the immunohistochemical technique. The gustatory cells of the taste buds are in synaptic contact with sensory nerve endings, and considering the taste buds strictly as specialized sensory organs, the amounts and distribution of some of the neurochemical markers were different to what we expected. For example, few structures showed immunoreactivity to the tachykinins substance P (SP), calcitonin gene-related peptide (CGRP), and neurokinin A (NKA) also for the peptides vasoactive intestinal polypeptide (VIP), neuropeptide tyrosine (NPY) and galanin, low amounts of immunoreactivity occurred. On the other hand, using antibodies to protein gene product 9.5 (PGP 9.5), protein S-100, and glutamate, numerous nerve fibres and/or immunoreactive cells were found in the fungiform papillae, in the epithelium, in the connective tissue and around blood vessels, as well as in or near taste buds. Incubation with the antibodies against somatostatin, enkephalin, bombesin, peptide histidine isoleucine amide (PHI), cholecystokinin (CCK)/gastrin and dopamine-beta-hydroxylase (DBH) was negative for the fungiform papillae. In conclusion, the present study has shown several immunoreactive structures using antibodies against certain neurochemical markers. Further investigations will hopefully correlate these morphological findings with functional taste perception data. Future studies of patients with taste disorders or other pathological changes correlated with taste and tongue will also be of utmost importance.

Neurokinin A and substance P vary independently in different regions of rat sensory neurons

Neurokinin A (NKA) and substance P (SP) are often co-localized in small sensory neurons and have been suggested to subserve similar roles. We have now compared tissue levels of NKA and SP in rat cervical dorsal root ganglia with those in the central and peripheral terminations of the same neurons. We found that NKA content was less than that of SP in dorsal root neuron perikarya and in two peripheral tissues (superior cervical ganglion and ear skin) containing SP axon terminals from cervical spinal ganglia; in a third peripheral tissue, trachea, equal amounts of NKA and SP were present. By contrast, in the spinal cord containing the central terminals of these sensory neurons there was almost twice as much NKA as SP. Our results indicate that, although NKA and SP are co-localized in sensory neurons, their levels vary independently, suggesting distinct functional roles.

Co-variation of neuropeptide Y, calcitonin gene-related peptide, substance P and neurokinin A in joint fluid from patients with temporomandibular joint arthritis

Forty-one patients (37 female and four male) with signs and symptoms of temporomandibular joint arthritis, were separated into two diagnostic groups (group I: inflammatory; group II: degenerative/non-specific joint disease). They were examined clinically, fluid was aspirated from the joint with saline and venous blood samples were collected at the same time. The joint fluid and plasma samples were analysed for neuropeptide-like immunoreactivity, i.e. neuropeptide Y (NPY-LI), calcitonin gene-related peptide (CGRP-LI), substance P (SP-LI) and neurokinin A (NKA-LI), using competitive radioimmunoassays. The aim was to investigate any co-variation of the peptides in the joint fluid and plasma. In group I, the median values of peptide concentrations in joint fluid were SP-LI = 129, CGRP-LI = 75, NKA-LI = 36 and NPY-LI = 676 pmol/l and in group II, SP-LI = 52, CGRP-LI = 64, NKA-LI = 45 and NPY-LI = 318 pmol/l. There were no significant differences between the groups for peptide concentrations. In group I, all the neuropeptides were strongly correlated. In group II, SP-LI and NKA-LI were strongly correlated while CGRP-LI was weakly correlated with NPY-LI and NKA-LI. Multiple step-wise regression analysis showed that most of the variation in NPY-LI, CGRP-LI and SP-LI in group I was explained by NKA-LI, but the regression did not reach statistical significance in group II.