Presence Of Neuropeptides Research Articles

Presence of neuropeptides in human nasal polyps.

The pathophysiological effects of non-cholinergic, non-adrenergic neuropeptides are well known in the nasal mucosa, but unclear in the polyps. Since the pathophysiological roles of neuropeptides depend on their presence in the target tissue, specimens of nasal polyps were removed from 20 patients and examined for the presence of vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), dopamine-beta-hydroxylase (DBH), substance P (SP) and calcitonin gene-related peptide (CGRP). To visualize these neuropeptide fibers, immunohistochemical staining by the peroxidase-anti-peroxidase method and color reaction by Nickel enhancement of diaminobenzidine (DAB) were used. Fine varicose neuropeptides immunostained fibers were predominantly distributed in the pedicle of the polyps. No neuropeptides were found in the mucosal epithelium and subepithelium. NPY fibers were predominantly seen around the thick wall vessels, whereas the VIP fibers were mainly to be found in close proximity to the submucosal glands and fairly close to the vessels. SP or CGRP fibers were not found in the polyps. VIP and NPY in the pedicle of the polyps may be present in connection with mucosal inflammation, tissue edema and cystic degeneration of the glands in the early stage of polyp formation. Thus these neuropeptides may contribute to the development and growth of nasal polyps.

Sensory and autonomic innervation of the facet joint in the rat lumbar spine.

The presence of sensory and autonomic nerves in the synovial membrane of the lumbar facet joint in rats was investigated by immunohistochemistry. Substance P and calcitonin gene-related peptide immunoreactivities, representing sensory nerves, were observed as varicose fibers in the synoviocyte layer. The fibers were predominantly nonvascular. The autonomic innervation was identified by the presence of neuropeptide Y- and tyrosine hydroxylase-positive fibers. Most of these fibers were found adjacent to or within blood vessel walls. Immunoreactivity to vasoactive intestinal polypeptide was seen in varicose nerve terminals in the synoviocyte layer, mostly unrelated to blood vessels. There is accumulating evidence of an involvement of both the sensory and sympathetic nervous systems in inflammatory joint disease. The neuropeptides now identified in lumbar facet joints may prove to play a significant role in the pathogenesis of low-back pain.

Characterization of atrial natriuretic peptide degradation by cell‐surface peptidase activity on endothelial cells

Atrial natriuretic peptide (ANP) is a fluid-regulating peptide hormone that promotes vasorelaxation, natriuresis, and diuresis. The mechanisms for the release of ANP and for its clearance from the circulation play important roles in modulating its biological effects. Recently, we have reported that the cell surface of an endothelial cell line, CPA47, could degrade 125I-ANP in the presence of EDTA. In this study, we have characterized this degradation of 125I-ANP. The kinetics of ANP degradation by the surface of CPA47 cells were first order, with a Km of 320 +/- 60 nM and Vmax of 35 +/- 14 pmol of ANP degraded/10 min/10(5) cells at pH 7.4. ANP is degraded by the surface of CPA47 cells over a broad pH range from 7.0-8.5. Potato carboxypeptidase inhibitor and bestatin inhibited 125I-ANP degradation, suggesting that this degradative activity on the surface of CPA47 cells has exopeptidase characteristics. The selectivity of CPA47 cell-surface degradation of ANP was demonstrated when 125I-ANP degradation was inhibited in the presence of neuropeptide Y and angiotensin I and II but not bradykinin, bombesin, endothelin-1, or substance P. The C-terminal amino acids phe26 and tyr28 were deduced to be important for ANP interaction with the cell-surface peptidase(s) based on comparison of the IC50 of various ANP analogues and other natriuretic peptides for the inhibition of ANP degradation. These data suggest that a newly characterized divalent cation-independent exopeptidase(s) that selectively recognizes ANP and some other vasoactive peptides exists on the surface of endothelial cells.

Neuropeptides Modulate Leukotriene B4 Mitogenicity Toward Cultured Human Keratinocytes

Neuropeptides released in skin from nerve fibers may interact with endogenous growth factors (or other mitogenic agents) to induce psoriasis lesions characterized by proliferating epidermal keratinocytes. The mitogenic effects of two neuropeptides, substance P (SP) and vasoactive intestinal peptide (VIP), on human adult and newborn keratinocytes were observed in the presence or absence of leukotriene B4 (LTB4) and leukotriene C4 (LTC4). In the presence of SP or VIP, LTB4 (but not LTC4) demonstrated substantial increase in thymidine incorporation into DNA, which was confirmed by cell-growth observations using the hexosaminidase assay. In the absence of either neuropeptide, LTB4 had only marginal effects, especially with adult (but not newborn) keratinocytes. With adult keratinocytes, LTB4 (but not LTC4) demonstrated synergy with both SP and VIP. VIP was mitogenic to keratinocytes at concentrations as low as 10(-12)M and exhibited a different dose-response curve depending on whether adult or newborn keratinocytes were used. The mitogenic effects of SP were abrogated by the SP antagonist spantide and those of VIP by the VIP antagonist [Ac-Tyr1, D-Phe2] growth-hormone-releasing factor (1-29) amide. This study suggests that the mitogenic effects of LTB4, which are elevated in psoriatic lesions, may be enhanced by the presence of neuropeptides, especially VIP. These effects can be reversed by antagonists that may have potential as drugs for the disease.

Brainstem peptidergic neurons projecting to the medial and lateral thalamus and zona incerta in the rat

The presence of neuropeptides in brainstem neurons that project to the medial and lateral thalamus and zona incerta has been studied in the rat. Brainstem neurons were retrogradely labeled from the medial and lateral thalamus and the zona incerta by colloidal gold-WGA-HRP and, after silver intensification of the retrograde label, their content of immunoreactivity for nine different neuropeptides was determined after colchicine administration. The medial thalamus and zona incerta both received a large peptidergic input and the lateral thalamus a smaller input from neurons in several brainstem nuclei. These were principally from the locus coeruleus, parabrachial nucleus, the dorsal raphe and the dorsal tegmentum. The principal input to the medial thalamus arose from neurotensin, neuropeptide Y and galanin neurons in the locus coeruleus, neurotensin neurons in the dorsal tegmentum, dynorphin neurons in the parabrachial nucleus and dorsal tegmentum, galanin neurons in the dorsal raphe, substance P neurons in the lateral and dorsal periaqueductal grey and calcitonin gene-related peptide neurons in the nucleus paragigantocellularis. The principal peptidergic input to the zona incerta was from dynorphin neurons in the nucleus of the solitary tract, bombesin neurons in the lateral reticular nucleus, calcitonin gene-related peptide and cholecystokinin neurons in the dorsal tegmentum, substance P, bombesin and galanin neurons in the locus coeruleus, dynorphin and substance P neurons in the lateral periaqueductal grey and cholecystokinin neurons in the substantia nigra, ventral tegmental nucleus and raphe linearis. The principal peptidergic input to the lateral thalamus came from calcitonin gene-related peptide and cholecystokinin neurons in the dorsal tegmentum, calcitonin gene-related peptide and galanin neurons in the locus coeruleus; substance P, neuropeptide Y, galanin and calcitonin gene-related peptide neurons in the dorsal raphe, substance P neurons in the lateral periaqueductal gray, galanin neurons in the nucleus interpedunculus and cholecystokinin neurons in the raphe linearis. In all these cases, from 25% to virtually all of the projection neurons in the brainstem nucleus could contain immunoreactivity to the neuropeptide. A lesser, but significant peptidergic input to the thalamus and zona incerta also arose from the trigeminal nucleus, the substantia nigra, the nucleus of the solitary tract, the lateral reticular nucleus, the interpeduncular nucleus, the raphe linearis, the paragigantocellularis, the inferior olive and ventral tegmental area. Overall, the neuropeptides most frequently present in the projection neurons were substance P, calcitonin gene-related peptide, galanin and cholecystokinin. Bombesin, neuropeptide Y, neurotensin and dynorphin were less common; and enkephalin was present in only a small percentage of projection neurons. Neurons in many of these brainstem nuclei receive nociceptive input from the spinal cord and then relay to the thalamus and zona incerta. Thus the neuropeptides we describe in these brainstem relay neurons could act to modulate the responses of thalamic neurons to their direct input from the spinothalamic tract.

Acute inflammation in the rat knee joint attenuates sympathetic vasoconstriction but enhances neuropeptide-mediated vasodilatation assessed by laser Doppler perfusion imaging

The effect of sympathetic nerve stimulation and topical application of substance P and calcitonin gene-related peptide on the blood flow of the exposed rat knee joint capsule was investigated. The responses of normal animals were compared to those of animals with acutely inflamed joints induced by intra-articular injection of 2% carrageenan. Laser Doppler perfusion imaging was used to examine the spatial distribution of blood flow in the knee joint capsule. Animals with acute joint inflammation showed markedly reduced vasoconstrictor responses to sympathetic nerve stimulation, but enhanced vasodilator responses to both substance P and calcitonin gene-related peptide when compared to normal. Prior application of either substance P or calcitonin gene-related peptide to the normal joint attenuated sympathetic vasoconstrictor responses. In the acutely inflamed knee, sympathetic vasoconstriction was replaced by a vasodilator response in the presence of neuropeptides. The reduced effectiveness of sympathetically mediated vasoconstriction and enhanced responsiveness to substance P and calcitonin gene-related peptide could contribute to the hyperaemia characteristic of inflamed joints.

Light-and electronmicroscopical immunohistochemical investigation of the innervation of the human carotid body.

The innervation of the carotid body has been extensively studied in several laboratory animals commonly used in chemoreceptor research. These studies revealed some features common to all species investigated - e. g. the presence of calcitonin gene-related peptide-immunoreactive (CGRP-IR) fibers of sensory origin (Kummer 1987, 1988; Kondo and Yamamoto 1988) but also some clear cut species differences - e. g. the presence of neuropeptide Y (NPY) containing sensory fibers in the rat (Czyczyk-Krzeska et al. 1991) but not in the guinea pig (Kummer 1990). Thus, data obtained in laboratory animals cannot be extrapolated to other species like man, and a detailed immunohistochemical study on the innervation of the human carotid body was initiated.

Postnatal Development of Sympathetic and Sensory Innervation of the Rhesus Monkey Ovary1

We have used immunofluorescence to study the postnatal development of the sympathetic and sensory innervation to the rhesus monkey (Macaca mulatta) ovary. Sympathetic nerves were identified as adrenergic by their content of tyrosine hydroxylase (TH)-like immunoreactivity and as peptidergic by the presence of neuropeptide Y (NPY). Fibers containing substance P (SP) or calcitonin gene-related peptide (CGRP)-like immunoreactivity were considered as sensory, whereas vasoactive intestinal peptide (VIP)-positive fibers were only defined as peptidergic because VIP may be present in both sympathetic and sensory nerves. Ovaries from neonatal (2-mo-old), juvenile (9-18-mo-old), peripubertal (3-3.5-yr-old), adult (9-14-yr-old), and senescent (20-27-yr-old) monkeys were studied. At all ages, with the exception of senescence, TH-, NPY-, and VIP-containing fibers were associated with follicles in different developmental stages. In peripubertal and adult animals, some primordial follicles were found to be selectively innervated by VIPergic fibers that almost completely encircled each follicle. Both sympathetic and VIP fibers were also detected in the interstitial tissue and associated with the ovarian vasculature at all ages. The number of sympathetic and VIP fibers increased significantly (p < 0.01) between 2 mo and 9-18 mo of age, and again increased (p < 0.01) around the age of puberty (approximately 3 yr of age). After this time, the number of NPY and TH fibers remained constant. Conversely, the number of VIP fibers decreased (p < 0.05) by 9-14 yr of age, but remained constant thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

The presence of neuropeptides in GABAergic and cholinergic rat cerebrocortical synaptosome sub-populations

GABAergic and cholinergic synaptosomes from rat cerebral cortex were isolated by a magnetic immunoaffinity technique, i.e. immunomagnetophoresis. These subpopulations were extracted and subjected to radioimmunoassay for four neuropeptides: Neuropeptide Y (NPY); vasoactive intestinal peptide (VIP); substance P (SP); and somatostatin (SRIF). In each of the sub-populations three of the four peptides were enriched in the sorted fraction compared with the mother fraction with respect to the cytosolic marker lactate dehydrogenase (LDH). In the GABAergic sub-population the order was SP>SRIF>NPY≥VIP whilst in the cholinergic sub-population they were enriched in the order VIP≥NPY>SP>SRIF. The presence of NPY has not previously been reported in cortical cholinergic neurons.

Localization of neuropeptides in the nervous system of the marine annelidSabellastarte magnifica

Immunohistochemical studies of the nervous system of Sabellastarte magnifica, a sedentary polychaete, showed the presence of neuropeptide expressing cells and fibers within the double ventral nerve cord. Immunoreactivity to cholecystokinin, neuropeptide Y, enkephalins, substance P, and FMRFamide was found to be present in specific populations of cells, identifiable by their location and by the neuropeptide they expressed. Fibers expressing the various neuropeptides were also observed in particular locations within the nerve cord. This characteristic distribution of the various neuron subgroups and fiber pathways may represent functional circuits within the nervous system of this annelid.

Interactions between neuropeptides and dexamethasone on the mitogenic response of rabbit spleen lymphocytes

The interactions between vasoactive intestinal peptide (VIP), substance P (SP), a somatostatin analog (SMS 201–995) and dexamethasone have been investigated on the Con A mitogenic response of rabbit spleen cells. The neuropeptide regulatory effects appeared to be time dependent: when added with the Con A mitogen, they inhibited (VIP) or did not modulate (SMS and SP) the rabbit lymphocyte proliferation and did not change the inhibitory effect induced by a dexamethasone preincubation. When added 18 h before the mitogen, they all induced an increase of the proliferative response at high concentration. The mitogenic response observed when adding dexamethasone to lymphocytes previously preincubated in the presence of neuropeptides was not different from control response except with SMS 10 −10 M. The similar lymphocyte responses obtained whatever the neuropeptide suggested that the immunomodulatory effect induced by a neuropeptide preincubation might be mediated by the induction of common effector(s).

Neuropeptide Y potentiates purinergic as well as adrenergic responses of the rabbit ear artery

The localisation of neuropeptide Y in the rabbit central ear artery and its pharmacological action on this preparation were investigated. Immunohistochemical studies demonstrated the presence of neuropeptide Y-like immunoreactivity in the perivascular nerves supplying the rabbit ear artery. Forty-eight hours after treatment with reserpine (5 mg/kg i.p. 48 h and 3 mg/kg i.p. 24 h prior to the experiment) catecholamine fluorescence in the rabbit central ear artery was abolished and the neuropeptide Y-like immunoreactivity was substantially reduced, suggesting that noradrenaline and neuropeptide Y were colocalised in sympathetic nerves. Contractile responses to exogenous noradrenaline (1 μM) and α,β-methylene ATP (1 μM) were both significantly potentiated following incubation with neuropeptide Y (0.3 μM); the degree of potentiation being similar for both agonists. Electrical field stimulation of the rabbit central ear artery (16 and 64 Hz) produced frequency-dependent contractile responses which were abolished by tetrodotoxin (1 μM) and which were significantly potentiated in the presence of neuropeptide Y (0.3 μM). The responses to stimulation at 16 Hz were enhanced to a greater extent than the responses at 64 Hz. After blocking the noradrenergic component of the neurogenic response with prazosin (1 μM), the residual purinergic component, at both 16 and 64 Hz, was significantly enhanced in the presence of neuropeptide Y. However, following desensitisation of the P 2-purinoceptor with α,β-methylene ATP, neuropeptide Y had no significant effect on the residual noradrenergic component. The results from this study show that neuropeptide Y has a postjunctional modulatory action on the responses elicited by electrical stimulation of the perivascular nerves in the presence and absence of prazosin as well as on the responses to the exogenously applied cotransmitters noradrenline and ATP.

Opioid-like immunoreactants in human cervical cancer

Cervical carcinoma cell lines produce several polypeptide hormones. While screening human cervical cancers for such factors we have found many tumors to be immunoreactive for opioid peptides. The tumors were collected at surgery or prior to actinotherapy, fixed in buffered formalin, paraffin-embedded, and immunocytochemically stained using the PAP method. The localization of opioid-like immunoreactivity was investigated using a primary antiserum recognizing the Tyr-Gly-Gly-Phe sequence common to all known opioid peptides. The presence of neuropeptide Y (NPY) and peptide histidine methionine (PHM), both known to be present in normal human cervical tissue, was also investigated using specific antisera. Controls included staining controls and absorption controls, using Sepharose-coupled antigen and were all negative. Out of 40 cervical carcinomas, 27 displayed varying numbers of opioid-immunoreactive cells. In 12 normal cervical specimens no specific staining was observed. None of the tumors displayed any NPY-like or PHM-like immunoreactivity. The growth of cervical carcinoma seems therefore to be accompanied by a destruction of the local peptidergic innervation of blood vessels and smooth muscle cells. The demonstration of opioid-like immunoreactants and the known immunoregulatory properties of these peptides, indicate that opioid peptides may be important in the regulation of growth of human cervical carcinoma.

Low concentrations of halothane produce hyperalgesia and attenuate descending inhibition

The presence of neuropeptides in propriospinal neurones has been determined in the rat. Few cervical neurones with long projections to the lumbar cord contained neuropeptides. Lumbar dorsal horn neurones with short intrasegmental projections, and ventral horn neurones with both short intra- and longer intersegmental projections commonly contained neuropeptides. From this, and previous studies, we summarise the organisation of the projections of spinal peptidergic neurones.

Propriospinal neurones are involved in the descending inhibition of lumbar spinal dorsal horn neurones from the midbrain

The presence of neuropeptides in propriospinal neurones has been determined in the rat. Few cervical neurones with long projections to the lumbar cord contained neuropeptides. Lumbar dorsal horn neurones with short intrasegmental projections, and ventral horn neurones with both short intra- and longer intersegmental projections commonly contained neuropeptides. From this, and previous studies, we summarise the organisation of the projections of spinal peptidergic neurones.

Neuropeptides in propriospinal neurones in the rat

The presence of neuropeptides in propriospinal neurones has been determined in the rat. Few cervical neurones with long projections to the lumbar cord contained neuropeptides. Lumbar dorsal horn neurones with short intrasegmental projections, and ventral horn neurones with both short intra- and longer intersegmental projections commonly contained neuropeptides. From this, and previous studies, we summarise the organisation of the projections of spinal peptidergic neurones.

Axonal tracing of autonomic nerve fibers to the superficial temporal artery in the rat

The origin of nerve fibers to the superficial temporal artery of the rat was studied by retrograde tracing with the fluorescent dye True Blue (TB). Application of TB to the rat superficial temporal artery labeled perikarya in the superior cervical ganglion, the otic ganglion, the sphenopalatine ganglion, the jugular-nodose ganglionic complex, and the trigeminal ganglion. The labeled perikarya were located in ipsilateral ganglia; a few neuronal somata were, in addition, seen in contralateral ganglia. Judging from the number of labeled nerve cell bodies the majority of fibers contributing to the perivascular innervation originate from the superior cervical, sphenopalatine and trigeminal ganglia. A moderate labeling was seen in the otic ganglion, whereas only few perikarya were labeled in the jugular-nodose ganglionic complex. Furthermore, TB-labeled perikarya were examined for the presence of neuropeptides. In the superior cervical ganglion, all TB-labeled nerve cell bodies contained neuropeptide Y. In the sphenopalatine and otic ganglia, the majority of the labeled perikarya were endowed with vasoactive intestinal polypeptide. In the trigeminal ganglion, the majority of the TB-labeled nerve cell bodies displayed calcitonin gene-related peptide, while a small population of the TB-labeled neuronal elements contained, in addition, substance P. In conclusion, these findings indicate that the majority of peptide-containing nerve fibers to the superficial temporal artery originate in ipsilateral cranial ganglia; a few fibers, however, may originate in contralateral ganglia.

Catecholaminergic and peptidergic nerves in naturally occurring and pheochromocytoma‐associated human brown adipose tissue

AbstractNoradrenergic and peptidergic innervations in naturally occurring and pheochromocytoma‐associated human perirenal brown adipose tissue were demonstrated. The presence of both parenchymal and periarterial noradrenergic nerve plexuses was revealed by the sucrose‐potassium‐glyoxylic‐acid (SPG) technique in all tissue samples. Immunohistochemical studies also indicated the presence of neuropeptide Y‐like, calcitonin gene‐related peptidelike, substance P‐like, and bombesinlike immunoreactive nerves in the adventitia of both inter‐ and intralobular arteries. At a more peripheral level, only neuropeptide Y‐like immunoreactive elements were observed in the parenchymal field. No somatostatinlike or enkephalinlike immunoreactivity was detected. The specific distributions of noradrenergic and peptidergic nerves were similar in both naturally occurring and pheochromocytoma‐associated brown adipose tissue. Thus these findings indicate a plurality of innervation in human perirenal brown fat.

Colocalization of substance P and γ-aminobutyric acid in amacrine cells of the cat retina

Substance P and γ-aminobutyric acid (GABA) were colocalized by immunocytochemistry in two subpopulations of amacrine cells in the cat retina. All of the cells which stained for substance P also showed GABA reactivity. However, there were many GABA-immunoreactive cells which did not stain for substance P. The presence of neuropeptides provides a basis for additional neurochemical characterization of the multiple populations of GABA immunoreactive cells.

Neuropeptide Y: presence in perivascular noradrenergic neurons and vasoconstrictor effects on skeletal muscle blood vessels in experimental animals and man

The presence of neuropeptide Y (NPY)-like immunoreactivity (-LI) in sympathetic perivascular nerves and the functional effects of NPY and noradrenaline (NA) on vascular tone were studied in skeletal muscle of various species. A dense network of NPY-LI was found around arteries and arterioles but not venules in the gluteus maximus muscle of man, gracilis muscle of dog, tenuissimus muscle of rabbit and quadriceps muscle of cat, rat, guinea pig and pig. The distribution of NPY-immunoreactive (-IR) nerves was closely correlated to the presence of tyrosine hydroxylase (TH) and dopamine-β-hydroxylase (DBH)-positive fibers, two markers for noradrenergic neurons. Double-staining experiments revealed that NPY- and TH-IR as well as NPY- and DBH-IR nerve fibers around arteries and arterioles were identical. The veins and venules, however, lacked or had a very sparse innervation of NPY-, TH- and DBH-positive fibers. The NPY- and TH-IR nerves in quadriceps muscle of the guinea pig were absent after treatment with 6-hydroxydopamine. Lumbosacral sympathetic ganglia from the same species contained many NPY-positive cells which were also TH- and DBH-IR. NPY-LI was also detected by radioimmunoassay in extracts of skeletal muscle from guinea pig, rabbit, dog, pig and man as well as of lumbosacral sympathetic ganglia. The content of NPY-LI in skeletal muscle was relatively low (0.1–0.4 pmol/g), whereas lumbosacral sympathetic ganglia had a much higher content (48–88 pmol/g). NPY (10 −7 M) contracted arterioles in the tenuissimus muscle of the rabbit to a similar extent (by 65%) as NA (10 −6 M), as studied by intravital microscopy in vivo. NPY had no effect on the corresponding venules while NA caused a slight contraction of these vessels. In vitro studies of small human skeletal muscle arteries and veins revealed that NPY was more potent than NA in contracting the arteries, and the highest concentration of NPY (5 × 10 −7 M) caused a contraction of a similar magnitude as NA 10 −5 M. NA contracted veins from human skeletal muscle, while NPY had only small effects. It is suggested that NPY, together with NA, could be of importance for sympathetic control of skeletal muscle blood flow.