Developmental studies on vasoactive intestinal peptide,substance P and calcitonin gene-related peptide in salivary glands of postnatal rats

The development of vasoactive intestinal peptide, substance P and calcitonin gene-related peptide in parotid, submandibular and sublingual glands of the male rat was followed by immunochemistry and immunocytochemistry. The total amounts of these peptides increased in surges during the first 8 weeks of the animal's life; one within 2–4 weeks and the other beginning 1–2 weeks later. Nerve fibres containing these peptides were present at birth showing a pattern of distribution similar to that in adults. During the first 4 weeks the nerve fibres increased in number.     

Substance P and vasoactive intestinal peptide in serotonin-induced nasal secretions in normal subjects

The aim of this study was to examine if nasal secretions contained substance P and/or vasoactive intestinal peptide. Serotonin nasal challenge was performed in 14 normal subjects 15 min after intranasal pretreatment (double-blind) with atropine, methysergide, chlorpheniramine or isotonic saline. Serotonin induced a dose dependent increase in secretion (P less than 0.05), and only pretreatment with atropine reduced the secretion (P less than 0.02). Substance P, measured by radioimmunoassay, was found in all of the examined secretions (n = 100) with a median concentration of 13.7 pmol/l (range 1.7-125.0). Serotonin challenge increased the concentration or content of substance P in a dose-related fashion (P less than 0.01). The different pretreatments did not affect the concentration of substance P. Vasoactive intestinal peptide was found in low concentration in 37% of the secretions with a median concentration of 0 pmol/l (range 0-50.0).     

Receptors involved in the nervous system regulation of polyamine metabolism in rat salivary glands

Polyamines are important for protein synthesis and tissue growth. In rat salivary glands, the activity of ornithine decarboxylase (ODC), the enzyme catalysing the formation of putrescine, and the content of putrescine, spermidine, spermine and N1-acetylspermidine were assayed after parasympathetic or sympathetic nerve stimulation in the presence of various autonomic receptor blockers. Increases in ODC activity occurred on activation of non-adrenergic and non-cholinergic receptors in response to parasympathetic nerve stimulation and on activation of alpha(alpha 1)- as well as of beta(beta 1)-adrenoceptors in response to sympathetic nerve stimulation. Moreover, in parotid glands, a beta(beta 1)-adrenoceptor-mediated inverse pathway for putrescine formation seemed to exist: from spermidine via N1-acetylspermidine.     

Protein secretion in salivary glands of cats in vivo and in vitro in response to vasoactive intestinal peptide

In anaesthetized cats exogenous vasoactive intestinal peptide failed to elicit any secretion of saliva from the submandibular and parotid glands. However, protein release from both glands occurred in response to VIP in the presence of alpha- and beta-adrenoceptor blocking agents and was dose-dependent. This response was revealed by means of a subsequent washout flow of saliva evoked by intravenous injections of methacholine or stimulations of the parasympathetic innervation. The submandibular glands responded to vasoactive intestinal peptide at a lower dose than the parotid glands. In the presence of atropine (but in the absence of adrenoceptor blockers), stimulation of the parasympathetic chorda-lingual nerve, which of itself elicited no secretion of saliva, contributed to the release of protein within the submandibular gland, since the output of protein in response to a subsequent stimulation of the sympathetic innervation was increased. Vasoactive intestinal peptide administered in combination with methacholine or during ongoing parasympathetic nerve-induced salivary secretion revealed positive interactions, particularly with respect to protein release. In-vitro protein release in response to vasoactive intestinal peptide was also demonstrated by perfusing small pieces of the two glands in the presence of muscarinic and adrenoceptor blockers. As in vivo, submandibular tissue responded at a lower concentration of vasoactive intestinal peptide than the parotid tissue. One to two weeks after combined parasympathetic and sympathetic denervation of the parotid glands, the glands were sensitized to vasoactive intestinal peptide when tested in vitro. It is concluded that vasoactive intestinal peptide or a structurally related peptide is a potential transmitter in the parasympathetic control of protein secretion in salivary glands of cats.     

Complementary action of substance P and vasoactive intestinal peptide on the rat parotid secretion

Augmentation of the rat parotid salivary secretion to intravenous injections of substance P (SP) occurred when SP was combined with vasoactive intestinal peptide (VIP), or stimulation of the auriculo-temporal nerve in the presence of atropine and the adrenergic blockers, dihydroergotamine and propranolol. The largest increase was obtained when SP (0.5 micrograms kg-1) was used together with subthreshold doses of VIP (84% at 0.05 micrograms kg-1 and 105% at 0.5 micrograms kg-1) and low frequency stimulation (92% at 2 Hz and 97% at 5 Hz), which did not produce any salivary secretion by itself. There was no facilitated secretion when VIP and nerve stimulation were combined. Amylase output was much larger (250-500%) when SP was combined with nerve stimulation (0.5-5 Hz) or VIP (0.005-5 micrograms kg-1) than when SP was used alone. Similar results were obtained in rats where the auriculo-temporal nerve was stimulated during the early phase (24-90 h) of Wallerian degeneration, when the nerve-induced responses were seemingly completely blocked. Our results are consistent with the hypothesis that both VIP and SP contribute to the atropine-resistant parotid secretion, and that they have a complementary role in the rat parotid exocrine function.     

Hyperprolactinemia reduces vasoactive intestinal peptide in the anterior pituitary glands of rats

The concentration of vasoactive intestinal polypeptide (VIP) in the anterior pituitary gland of female rats was significantly reduced by pituitary implants, prolactin-secreting tumours or dopamine blockade-induced hyperprolactinemia. Oestradiol implants increased plasma prolactin (PRL) to 12 times and increased pituitary VIP to 3.5 times that of controls after one week. The dopamine agonist bromocriptine significantly reduced pituitary VIP at doses within the clinically used range. These results provide evidence for a suppressive effect of plasma PRL on pituitary VIP, which may be effected by a dopaminergic mechanism, but is over-ridden by oestrogen.     

Vasoactive intestinal peptide evoked secretion of fluid and protein from rat salivary glands and the development of supersensitivity

Vasoactive intestinal peptide (VIP) injected intravenously was found to induce a flow of saliva from both the parotid and the submaxillary gland in the rat. The secretion was slow in onset. The amount of saliva secreted from the parotid gland was less than that from the submaxillary gland. Parotid saliva was very viscous. VIP-evoked parotid saliva was more protein rich than both submaxillary saliva and saliva secreted in response to other sialagogue drugs including the beta-adrenergic receptor agonist isoprenaline. The effect of VIP was direct; it occurred after removal of the adrenals, after degeneration of intraglandular nerves and in the presence of autonomic blockers. A supersensitivity to VIP was demonstrable. In the parotid and the submaxillary glands the secretory response to VIP was enlarged following parasympathetic denervation and decentralization, respectively, while after sympathetic denervation supersensitivity was only found to develop in the submaxillary gland.     

Ontogeny of vasoactive intestinal peptide gene expression in rat brain

Vasoactive intestinal peptide (VIP) expression was studied during rat brain development using in situ hybridization histochemistry with a 48mer, S³⁵-ATP-labeled probe. First expression of VIP was found in the lateral thalamus at E17, in a region later recognized as the reticular nucleus. At E19, VIP mRNA was also found in the hypothalamus, especially the suprachiasmatic nucleus. The only other prenatal localizations were the cortex and the brainstem. VIP expression continously matured during the first three postnatal weeks, and adultlike patterns were found at P22, when cerebral cortex, ventrolateral and reticular thalamic nuclei, suprachiasmatic nucleus were the regions with most prominent VIP expression. These results demonstrate the relatively late appearance of VIP gene expression in the rat forebrain as compared with peptides like SRIF and CCK, suggesting it does not have a major role in early brain maturation.     

血管活性肠肽对大鼠Leydig细胞的免疫调节作用

目的:研究血管活性肠肽(VIP)对大鼠睾丸间质细胞(Leydig细胞)免疫功能的调节。方法:以VIP作用于溶脲脲原体(UU)感染的SD大鼠及大鼠Leydig细胞为研究对象,观察VIP对大鼠Leydig细胞分泌的细胞因子(IL-1、IL-6及TGF-β)和FasL表达的调节,从体外及动物整体水平来探讨VIP对大鼠Leydig细胞免疫功能的调节。结果:在睾丸局部感染时,VIP能调节Leydig细胞IL-1、IL-6、TGF-β及FasL的分泌和表达格局;同时VIP对大鼠睾丸局部免疫豁免的调节和维持也起到一定的作用。结论:VIP能调节大鼠Leydig细胞的免疫功能,并参与调节大鼠睾丸局部的免疫豁免。     

Changes in diamine and polyamine metabolism in the duct-ligated submaxillary and sublingual glands of the rat

Duct-ligation of salivary glands is known to cause disappearance of acini, while ductal elements persist. In the present investigation the duct-ligated submaxillary and sublingual glands increased in weight by 45-60% 3 days postoperatively, while they weighed 48-56 and 63-64% less than their contralateral glands 10 and 21 days postoperatively. In the duct-ligated glands putrescine increased markedly both in terms of total amount and in terms of concentration, while spermidine and spermine decreased; histamine, in terms of concentration, was initially reduced but increased markedly later. As to total amount histamine tended to increase along time. The histamine-forming enzyme, histidine decarboxylase, and the putrescine-forming enzyme, ornithine decarboxylase, showed higher activities in the duct-ligated submaxillary glands than in the contralateral glands. Di- and polyamines and their synthesizing enzymes are considered to increase in growing tissue. The present results of increased amine levels and enzyme activities are discussed in relation to previous findings of ductal goblet cell hyperplasia following duct-ligation and of increases of polyamines in cystic fibrosis.     

Antibodies to fragments of provasoactive intestinal peptide reveal subpopulations of vasoactive intestinal peptide containing neurons in the rat gut

The cellular origin of peptides derived from preprovasoactive intestinal peptide has been studied in rat stomach and ileum. Antisera specific for the C-terminal regions of the N-terminal flanking peptide (preprovasoactive intestinal peptide 22-80), bridging peptide (preprovasoactive intestinal peptide 111-124), C-terminal flanking peptide (preprovasoactive intestinal peptide 156-170) and vasoactive intestinal peptide were used in immunohistochemical studies on sections and whole mounts. All four antisera stained nerve fibres and cell bodies in the stomach and intestine. However, there were distinct differences in the pattern of colocalization of peptides derived from provasoactive intestinal peptide. In the sub-mucous plexus of the ileum virtually 100% of neurons reacting with vasoactive intestinal peptide antibodies also reacted with antibodies to the other three peptides. In contrast, in the stomach, while all vasoactive intestinal peptide-immunoreactive neurons of the myenteric plexus contained C-terminal flanking peptide- and bridging peptide-like immunoreactivity, only 50% of these cells reacted with the antiserum to N-terminal flanking peptide. The data indicate that in a population of neurons in the myenteric plexus of the rat stomach, preprovasoactive intestinal peptide is processed in such a way that the antigenic determinant of the N-terminal flanking peptide is not produced. In a second population of enteric neurons in the stomach, and in the intestine, it appears that processing of preprovasoactive intestinal peptide results in the production of peptides reacting with antibodies to vasoactive intestinal peptide, the flanking and bridging peptides.     

Effect of vasoactive intestinal polypeptide on glycogen metabolism in rat hepatocytes

The effects of vasoactive intestinal polypeptide (VIP) on several enzymes of glycogen metabolism in rat hepatocytes were compared with those of glucagon and of vasopressin (ADH). VIP caused phosphorylase activation and glycogenolysis in hepatocytes from fed rats. In hepatocytes from fasted rats incubated with glucose, lactate, and pyruvate, VIP inhibited net glycogen deposition, inactivated glycogen synthase, and activated phosphorylase. VIP was about 100-fold less potent than glucagon and 1,000-fold less potent than ADH in causing activation of phosphorylase. The ability of VIP to activate phosphorylase was not altered by chelation of the calcium in the medium. The half maximal effective doses of VIP for both phosphorylase activation and stimulation of glycogenolysis were 10-30 nM. Treatment with VIP, ADH, or glucagon did not decrease phosphorylase phosphatase activity. Each of these hormones, however, lengthened the lag time before synthase phosphatase activity was expressed in vitro. Other gut hormones tested did not affect hepatocyte glycogen metabolism. These results do not support the concept of physiologic control of hepatic glycogen metabolism by VIP or by other gut hormones.     

After axotomy, substance P and vasoactive intestinal peptide expression occurs in pilomotor neurons in the rat superior cervical ganglion

Autonomic sympathetic postganglionic neurons normally express distinct combinations of neuropeptides which are often highly correlated with the projection of the neurons. When sympathetic postganglionic neurons are axotomized, they can express quite different neuropeptides, notably substance P, vasoactive intestinal peptide or galanin. In this study, we have examined rat sympathetic postganglionic neurons in the superior cervical ganglion that project to the skin, the vasculature of the skeletal muscle or to the submandibular salivary gland, and assessed whether the neuropeptides that they express after axotomy depend on which target tissue they previously innervated. In all three populations, around half of the postganglionic neurons expressed galanin after axotomy. In contrast, only skin-projecting neurons showed a significant increase in the number of neurons that expressed substance P (22%) and vasoactive intestinal peptide (17%) following axotomy. Within the skin-projecting neurons, as judged on the basis of cell body size, substance P and vasoactive intestinal peptide were expressed predominantly in pilomotor neurons, but only rarely were the two neuropeptides present in the same nerve cell body.In conclusion, we have demonstrated that three different neuropeptides, which can be induced by axotomy in postganglionic neurons, follow quite different patterns of expression when they are viewed in relation to the function of the postganglionic neurons in the superior cervical ganglion.     

Expression of histamine and vasoactive intestinal peptide (VIP) receptors in immortalized rat fetal intestinal cells

Four intestinal cell lines derived from rat fetuses at 19 days of gestation were successfully propagated after electroporation in the presence of different recombinant DNAs containing the viral oncogenes E1A from Adenovirus 5 and large T from SV40 or Polyoma. These immortalized intestinal cells, designated SLC, possess several properties observed in the parent cells of this tissue, including the expression of cytoplasmic villin, enkephalinase and retention of VIP receptors. In contrast, histamine elevated cAMP levels in the SLC cell lines only. the data suggest that the transfection of fetal rat intestinal cells by E1A and large T is associated with the induction of functional histamine receptors coupled with the Gs/Gi regulatory proteins of adenylate cyclase.     

Myocardial vasoactive intestinal peptide and fibrosis induced by nitric oxide synthase inhibition in the rat

AIMS: In both normotensive and hypertensive rats, the degree of myocardial fibrosis is inversely correlated with the concentration of vasoactive intestinal peptide (VIP) in the myocardium. Treatment with nitric oxide (NO) synthase inhibitors also causes myocardial fibrosis. In this study, we sought to determine whether the myocardial fibrosis induced by treatment with the NO synthase inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME) was also associated with depletion of VIP in the myocardium. METHODS: Male Wistar Kyoto (WKY) and spontaneous hypertensive rats (SHR) rats treated with l-NAME were randomized to low, intermediate or high salt content diets. After 4 weeks, the hearts were harvested, the degree of fibrosis quantified and VIP concentration measured. RESULTS: In WKY, systolic blood pressure increased with increasing dietary sodium (P < 0.05). Myocardial fibrosis also increased with increasing dietary sodium (P < 0.005). Myocardial VIP concentration decreased with increasing dietary sodium (P < 0.025). In contrast, in the SHR treated with l-NAME, systolic blood pressure increased but the increase was not affected by sodium intake. Further, myocardial fibrosis and myocardial VIP were unchanged by increased dietary sodium. Higher doses of l-NAME in the SHR did not increase the systolic blood pressure, increase the degree of myocardial fibrosis or decrease the myocardial concentration of VIP. These differences in myocardial VIP concentration may reflect differing effects of l-NAME on VIP metabolism, as l-NAME increased VIP metabolism in the WKY (P < 0.05) but did not change VIP metabolism in the SHR. CONCLUSIONS: We conclude that depletion of VIP in the myocardium is associated with increasing myocardial fibrosis in l-NAME treated WKY. As VIP depletion occurs in other models of myocardial fibrosis, it appears to be a common mechanism. Myocardial VIP depletion may therefore be a new and important factor in the pathogenesis of cardiac fibrosis.     

Immunohistochemical localization of receptors for vasoactive intestinal peptide and substance P in human trachea.

BACKGROUND: Tissue sections of human cervical trachea were processed for immunohistochemical demonstration of receptors for substance P [using an anti-SP anti-idiotypic antiserum directed toward the ligand binding site of the receptor (Couraud J-Y, Escher ED, Regoli D, Imhof V, Rossignol B, Pradelles P. Anti-substance P anti-idiotypic antibodies: Characterization and biological activities. J Biol Chem 1985;260:9461-9; Couraud J-Y, Maillet S, Grassi J, Frobert Y, Pradelles P. Characterization and properties of anti-substance P antiidiotypic antibodies. Methods Enzymol 1989; 178:275-300)] and vasoactive intestinal peptide (VIP; utilizing a monoclonal antibody toward VIP receptors of an adenocarcinoma cell line (Pichon J, Hirn M, Muller J-M, Mangeat P, Marvaldi J. Anticell surface monoclonal antibodies which antagonize the action of VIP in a human adenocarcinoma cell line (HT29). EMBO J 1983;2:1017-22)], respectively. Mucus cells of the submucosal glands (identified by periodic acid Schiff staining) and neuroendocrine cells of the respiratory epithelium (identified by immunoreactivity to protein gene product 9.5) displayed intense VIP receptor-immunoreactivity. Other tissue components known to respond to exogenously administered VIP, e.g., trachealis muscle, lacked VIP receptor-immunoreactivity, indicating that the monoclonal antibody did not label all receptor subtypes. In accordance with the known pharmacological actions of substance P upon the airways, the anti-substance P receptor antibody labeled the trachealis muscle, submucosal glands, and respiratory epithelium, predominantly at the luminal aspect. Since substance P as well as the structurally related tachykinin, neurokinin A, competed with the anti-receptor antibody in binding to the tissue section, it is likely that both NK-1 and NK-2 receptor subtypes were labeled. The present histochemical approach to localize peptide receptors in the trachea allowed precise analysis of distribution unreached by previous studies using autoradiography. Together with pharmacological data, these morphological findings contribute to the understanding of the sequences of events evoked by the neuropeptides, substance P and VIP, in the human trachea.     

Nitric oxide-dependent in vitro secretion of amylase from innervated or chronically denervated parotid glands of the rat in response to isoprenaline and vasoactive intestinal peptide

The basal in vitro release of amylase was similar from rat parotid lobules of innervated and chronically denervated glands and was unaffected by the inhibitors used in this study. The secretion of amylase induced by isoprenaline or vasoactive intestinal peptide (VIP) was reduced by one-third to one-half from the lobules of the innervated glands and even more so from the lobules of the denervated glands by ODQ, an inhibitor of soluble guanyl cyclase which is activated by nitric oxide (NO) and catalyses the cGMP production. The use of N (omega)-propyl-L-arginine (N-PLA) revealed that the evoked secretion of amylase in the denervated glands depended on the activity of neuronal type NO synthase to synthesize NO. Since the denervated gland is virtually devoid of NO synthase-containing nerve fibres, the neuronal type NO synthase was most probably of a non-neuronal source. NO-dependent amylase secretion was agonist related, since amylase secretion evoked by bethanechol and neuropeptide Y was not reduced by ODQ or N-PLA. Hence, under physiological conditions, activation of beta-adrenoceptors (sympathetic activity) and VIP receptors (parasympathetic activity) is likely to cause secretion of parotid amylase partly through a NO/cGMP-dependent intracellular pathway involving the activity of neuronal type NO synthase, possibly of acinar origin.     

P物质、血管活性肠肽和乙酰胆碱能神经在大鼠肠道内的分布及其关系

应用乙酰胆碱酯酶(AChE)组织化学和PAP免疫组织化学方法,比较观察P物质(SP)、血管活性肠肽(VIP)和AChE三种阳性神经元在大鼠十二指肠、空肠、回肠、结肠和直肠内的分布特征及其相互关系。结果显示:SP、VIP、AChE阳性神经神经元和纤维均分布于肠壁各层,从十二指肠、空肠到回肠逐渐增多,但从结肠到直肠则逐渐减少;AChE阳性神经元或纤维在肠壁各层最丰富,其中VIP以粘膜层和粘膜下神经丛较丰富,SP以肠肌丛较丰富;三者的分布密度为AChE>VIP>SP。AChE、SP和VIP阳性神经元胞体及神经纤维在不同肠段的分布密度有明显差异(P<0.05),提示可能与不同肠段肠动力调节功能有关。     

扬子鳄卵巢内血管活性肠肽、神经肽Y和P物质的分布

目的:观察扬子鳄卵巢内血管活性肠肽（vasoactive　intestinal　peptide,VIP）、神经肽Y（neuropeptide Y,NPY）和P物质（substance P,SP）的分布情况。方法:免疫荧光法。结果:扬子鳄卵巢内的VIP免疫反应（VIP-immunoreac-tive,VIP-IR）阳性神经纤维呈波浪状,部分包绕卵泡,大部分交织在卵泡间血管周围,并构成较密集的网络;SP和NPY免疫反应（SP-and NPY-immunoreactive,SP-和NPY-IR）阳性神经纤维均为点线状,主要沿卵泡间血管周围分布,其中,部分NPY-IR纤维也构成较密集的网络。切片中均未见到三种肽能神经元的细胞体。结论:扬子鳄卵巢内存在有VIP、NPY和SP阳性神经纤维分布,主要位于卵泡间血管周围。     

血管活性肠多肽及降钙素基因相关肽对大鼠腹腔肥大细胞组胺释放的作用

目的:研究血管活性肠多肽(Vasoactive intestinal peptide,VIP)及降钙素基因相关肽(Calcitonin gene relatedpeptide,CGRP)对大鼠腹腔肥大细胞脱颗粒的诱导作用;了解神经多肽与肥大细胞的相互关系。方法:分离、纯化SD大鼠腹腔肥大细胞;应用不同浓度的VIP和CGRP作用于大鼠腹腔肥大细胞后,同位素放射液态闪烁法检测肥大细胞的组胺释放、45Ca摄入的变化;同时观察大鼠腹腔肥大细胞经5×10-6mol/L VIP受体抑制剂L-8-K处理后,对VIP诱导脱颗粒作用的影响。结果:5×10-6mol/L的VIP作用后大鼠腹腔肥大细胞组胺释放及45Ca摄入明显增加,并且这种变化与VIP呈剂量效应关系;CGRP对大鼠腹腔肥大细胞组胺释放无诱导作用;L-8-K作用后,肥大细胞对VIP的诱导活化作用无改变。结论:VIP可引起肥大细胞钙内流增加,进一步诱导肥大细胞脱颗粒、释放组胺等生物活性物质,产生生物学效应;这种作用是受体非依赖性的,且与VIP的分子构型有关。