Calcitonin gene-related peptide-like immunoreactivity in nerve fibers in the human skin. Relation to fibers containing substance P-, somatostatin- and vasocactive intestinalpolypeptide-like immunoreactivity

Calcitonin gene-related peptide-like immunoreactivity was demonstrated in in sensory nerve fibers in the epidermis and dermis as free nerve endings and around blood vessels and hair follicles of the human finger pad and arm skin. The vast majority of the calcitonin gene-related immunoreactive fibers was shown to display also substance P-like immunoreactivity and a few fibers in the dermis were somatostatin positive. No fibers displaying both substance P and somatostatin-like immunoreactivity were found but a few substance P immunoreactive fibers in the dermis-epidermis region were found to contain also vasointestinal polypeptide-like immunoreactivity. In the sweat glands, abundant calcitonin gene-related peptide positive, but substance P negative, fibers were observed with a similar distribution pattern as the vasoactive intestinal polypeptide immunoreactive fibers and these fibers were suggested to be of sympathetic origin.

pH-dependent accumulation of the vesicular stomatitis virus glycoprotein at the ends of intact virions

The electron microscope was employed to examine the effect of pH on the distribution of the vesicular stomatitis virus glycoprotein (VSV G-protein) on the surface of intact virions. Both rotary shadowed and negatively stained preparations demonstrated that whereas at neutral pH the glycoprotein was evenly distributed along the virus membrane, at pH 5.5 it was concentrated at the ends giving the overall virion a distinct bilobed or bipolar morphology. Negatively stained specimens showed that the shape of individual glycoprotein spikes was not greatly different at pH 5.5 compared to pH 7.5. The most dramatic effect was in their distribution along the virus membrane. The uniform glycoprotein distribution observed at neutral pH changed rapidly (t1/2 less than 1 min at 21 degrees) to the bipolar state when the pH of the medium was shifted from pH 7.5 to pH 5.5, and it reappeared somewhat more slowly (t1/2 = 2 min at 21 degrees) when the virus was returned to pH 7.5. Our observations support the view that the VSV glycoprotein is able to move laterally in the plane of the virion membrane to produce the terminal G-protein clusters found at low pH. They further suggest that the virion ends may be preferred as sites for the low pH-dependent membrane fusion process involved in initiation of infection by VSV.

Isolation from porcine intestinal extracts of a cholecystokinin-like peptide and a peptide with homology to cytochrome oxidase polypeptide VII and chymodenin

A number of different forms of cholecystokinin (CCK) exist in the brain and intestine. Gel permeation and ion exchange chromatography and high performance liquid chromatography have been used to isolate a peptide from partially purified porcine intestinal extracts with N-terminal homology to porcine brain CCK-58. This peptide contracted both the guinea pig ileum longitudinal muscle and gallbladder muscle and these responses were inhibited by dibutyryl cyclic GMP or proglumide. The potency was approximately 1/100 of that of CCK-8. The reason for this low potency is unclear, but it is possible that a critical part of the biologically active region is modified or that it is a truncated form of CCK-58. A further peptide was isolated with a sequence homologous to cytochrome oxidase polypeptide VII and chymodenin.

Hyperimmunization alters Fc gamma antigenicity. Linkage to glycosylation

Rabbits were hyperimmunized with streptococcal vaccine to produce hyperimmune (HI) IgG, and both HI IgG and autologous preinoculation (PI) IgG were used to prepare Fc gamma. mAb raised against these, and deglycosylated PI Fc gamma preparations were subsequently used to determine if antigenic differences existed between autologous HI and PI Fc gamma. Although the majority of mAb examined did not discriminate between the two sources of Fc gamma, several mAb exhibited remarkable specificity for autologous HI Fc gamma. We did not detect any mAb which exhibited the converse specificity. Of the mAb chosen for study, all except one appeared specific for determinants located in C gamma 2; the exception specifically reacted with pFc', and did not discriminate between the two Fc preparations. Importantly, partial deglycosylation of autologous PI Fc gamma led to equivalent reactivity with previously HI-specific mAb. The results of this study provide immunologic evidence that abnormal C gamma 2 structures exist prior to and reach serologically detectable levels during the hyperimmune response in these animals, apparently as a result of glycosylation pattern alterations within the Fc region. Such autoantigenic differences could account for the induction of RF under these conditions, and perhaps in certain human arthritic diseases as well.

Hyperimmunization alters Fc gamma antigenicity. Linkage to glycosylation

Rabbits were hyperimmunized with streptococcal vaccine to produce hyperimmune (HI) IgG, and both HI IgG and autologous preinoculation (PI) IgG were used to prepare Fc gamma. mAb raised against these, and deglycosylated PI Fc gamma preparations were subsequently used to determine if antigenic differences existed between autologous HI and PI Fc gamma. Although the majority of mAb examined did not discriminate between the two sources of Fc gamma, several mAb exhibited remarkable specificity for autologous HI Fc gamma. We did not detect any mAb which exhibited the converse specificity. Of the mAb chosen for study, all except one appeared specific for determinants located in C gamma 2; the exception specifically reacted with pFc', and did not discriminate between the two Fc preparations. Importantly, partial deglycosylation of autologous PI Fc gamma led to equivalent reactivity with previously HI-specific mAb. The results of this study provide immunologic evidence that abnormal C gamma 2 structures exist prior to and reach serologically detectable levels during the hyperimmune response in these animals, apparently as a result of glycosylation pattern alterations within the Fc region. Such autoantigenic differences could account for the induction of RF under these conditions, and perhaps in certain human arthritic diseases as well.

Coexistence of TRH with other neuroactive substances in the rat central nervous system

Colocalization of thyrotropin-releasing hormone-like immunoreactivity with other neuroactive substances was examined immunohistochemically in colchicine-treated rat brains using double-staining or elution-restaining methods. Thyrotropin-releasing hormone-like immunoreactivity was shown to be located in the same neurons as: 1. enkephalin-, gamma-amino butyric acid- and tyrosine hydroxylase-, but not somatostatin-like immunoreactivity in the glomerular layer of the olfactory bulb 2. oxytocin- and cholecystokinin-, but not vasopressin-like immunoreactivity in the supraoptic nucleus 3. cholecystokinin-like immunoreactivity in posterior pituitary 4. enkephalin-like immunoreactivity in the perifornical area of the hypothalamus and 5. neuropeptide Y- and neurotensin-like immunoreactivity in the periaqueductal central grey. These findings provide further examples of coexistence of thyrotropin-releasing hormone with classical neurotransmitters and/or peptides in the rat central nervous system.

Inhibitory actions of tachykinins and neurokinins on release of somatostatin-like immunoreactivity from the isolated perfused rat stomach

The present experiments were designed to test the effect of tachykinins and neurokinins on release of somatostatin-like immunoreactivity (SLI) from the isolated perfused stomach. Physalaemin, substance P, kassinin, eledoisin, neurokinin A and neurokinin B inhibited basal SLI release in a dose-dependent manner (1 X 10(-9) to 1 X 10(-7) M). Among all the peptides, physalaemin and substance P were the least potent, whereas kassinin, eledoisin, neurokinin A and B were the more potent compounds in suppressing SLI release. It is proposed that this inhibitory action of tachykinins and neurokinins was mediated by the substance P-K or neurokinin-2 receptor subtype in which kassinin, neurokinin A and eledoisin have been shown to be the more potent agonists. The present study also showed that the effect of neurokinin A, neurokinin B and kassinin was not due to an action involving release of acetylcholine as cholinergic antagonists did not block the SLI inhibitory effect. This suggests that these peptides acted directly on somatostatin containing D-cells.

NMR-invisible lactate in blood plasma

Resonances for lactate are broadened in 500 MHz 1H NMR spectra of human blood plasma and only about one-third is visible in Hahn spin-echo spectra. Similar effects are observed for some other carboxylate anions. Lactate added to the high-Mr fraction of plasma can give rise to peaks which are too broad to observe in either single-pulse or spin-echo spectra. Addition of agents such as NH4Cl of SDS dramatically increases the intensities of lactate peaks. Some glycoproteins appear to broaden lactate resonances.

TRH-like immunoreactivity in endocrine cells and neurons in the gastro-intestinal tract of the rat and guinea pig

By use of the indirect immunofluorescence technique, the cellular localization of thyrotropin-releasing hormone (TRH) was studied in the gastrointestinal tract of rats and guinea pigs of different ages. TRH-like immunoreactivity (LI) was observed in many pancreatic islet cells of young rats and guinea pigs but only in single cells of 6-month-old rats. In aged guinea pigs, a reduction in the number of TRH-positive cells was evident; however, numerous strongly fluorescent cells were still present. In the guinea pig, TRH-LI was in addition observed in gastrin cells in the stomach. TRH-positive nerve fibers occurred in the myenteric plexus of the oesophagus, stomach and intestine of the rat, and in the muscle layers of the guinea pig. These results suggest a functional role of TRH both as hormone and neuroactive compound in various portions and sites of the gastro-intestinal tract of the rat and guinea pig.

Plasma enteroglucagon and small bowel cytokinetics in rats fed soluble nonstarch polysaccharides

The influence of dietary fiber on plasma glucagon and enteroglucagon (EG) and on ileal crypt cell production rate (CCPR) was assessed in the rat. A fiber-free semisynthetic diet and diets containing insoluble cellulose, Na-carboxymethylcellulose (CMC), guar gum, pectin, gum arabic, methylcellulose (MC), and hydroxypropylmethylcellulose (HPMC) at 10 g/100 g were fed for 14 d. Animals given soluble polysaccharides had plasma EG levels significantly higher than animals given insoluble cellulose, but only those fed the most viscous gums showed evidence of increased mucosal cell proliferation in the distal ileum. It was concluded that viscous nonfermentable polysaccharide gums stimulate the release of EG in the rat by slowing the absorption of nutrient, whereas the nonviscous polysaccharide gum arabic, or its breakdown products, probably directly stimulate mucosal endocrine cells. The failure of gum arabic to stimulate CCPR despite increased plasma EG indicated that EG alone is not a sufficient stimulus for increased mucosal cell proliferation.

Cysteamine-induced reduction in gastrointestinal somatostatin: evidence for a region-specific loss in immunoreactivity

Administration of cysteamine (beta-mercaptoethylamine; 2-aminoethanethiol) to rats has been shown to decrease the levels of somatostatin-like immunoreactivity (SLI) in the gastrointestinal tract and pancreas but its mode of action is unclear. In the current study the effect of cysteamine on gastrointestinal and pancreatic SLI has been studied using two antisera with different regional specificities. In addition, the in vitro effect of cysteamine on SS-14 and SS-28 has been studied by high-performance liquid chromatography (HPLC). Characterization of the two antisera (AS 26.3.2 and AS 1001) with a range of analogs of SS-14 revealed that both were directed against the midportion of the molecule but that AS 1001 was also sensitive to changes at the N- and C-termini. Tissue extracts from cysteamine-treated rats measured with AS 26.3.2 showed no significant change for the stomach, jejunum or pancreas but duodenal levels were reduced. With AS 1001 SLI levels were reduced in all tissues. Gel permeation chromatography of stomach extracts measured with AS 1001 showed a reduction in both SS-14 and SS-28. With AS 26.3.2 an increase in SLI eluting prior to the SS-14 peak occurred explaining why no significant reduction in total SLI was detected. With duodenal extracts the elution profiles with AS 1001 reflected the large reduction in total SLI whereas with AS 26.3.2 a smaller reduction occurred. Both SS-14 and SS-28 were reduced. HPLC analysis of SS-14 and SS-28 following incubation with cysteamine in vitro showed a time-dependent decrease in both somatostatin species with absorbance at 280 nm was measured. New peptide peaks which developed were not all detectable by radioimmunoassay with either antibody. The results suggest that cysteamine causes a change in the structure of somatostatin which probably first involves a reduction of the disulphide bridge and then the N- and C-terminal regions of the molecule thus making it unmeasurable by antisera sensitive to changes in these regions.

Enteroinsular axis

A physiological role for GIP as an insulinotropic hormone involved in the enteroinsular axis has been established and ingestion of glucose, fatty acids and certain amino acids will produce an increase in circulating IR-GIP levels. The insulinotropic action of GIP is glucose concentration dependent in normal animals. A role for GIP in NIDDM is equivocal although several studies have demonstrated elevated serum levels. Animal models have indicated a disturbance of GIP receptor function associated with hyperinsulinaemia, i.e. lowering of the minimum glucose concentration at which GIP is insulinotropic.

The effect of mannitol and dopamine on the renal response to thoracic aortic cross-clamping

Postoperative renal failure and insufficiency are important complications of operations that require thoracic aortic cross-clamping. Successful application of pharmacologic methods to protect renal function would be clinically useful. The ability of mannitol and dopamine to prevent renal dysfunction in a canine model of thoracic aortic cross-clamping was studied. Twenty animals were divided into four equal groups, and all underwent thoracic aortic cross-clamping for 60 minutes. An intra-aortic infusion of saline (control), mannitol, dopamine, or mannitol plus dopamine was started before, and continued during, the period of aortic occlusion. Glomerular filtration rate was significantly depressed 60 minutes after clamp release, and although there was some recovery in treated animals 150 minutes after clamp release, it remained significantly decreased (52% to 73% of baseline values, p less than 0.01). Renal blood flow was significantly reduced 60 minutes after clamp release, and there was no recovery in any group at 150 minutes (38% to 56% of baseline values, p less than 0.01). No significant differences in osmolar clearance or fractional excretion of sodium were evident between groups. These data reveal that the profound reductions in glomerular filtration and renal blood flow induced by thoracic aortic cross-clamping were not attenuated by mannitol or dopamine and suggest that efforts to protect renal function should be directed toward improving renal blood flow in the post-clamp period.

Existence and coexistence of calcitonin gene-related peptide, vasoactive intestinal polypeptide- and somatostatin-like immunoreactivities in spinal cord motoneurons of developing embryos and post-hatch chicks

By use of immunocytochemical methods, it is shown that immunoreactive calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and somatostatin (SOM) are present in motoneurons in the chicken spinal cord. While CGRP-like immunoreactivity (LI) is present in numerous motoneurons both before and after hatching, SOM- and VIP-LI markedly decline at the end of the embryonic period. Evidence is also provided for coexistence of some of these peptides in certain spinal motoneurons.

Eosinophilic granuloma of the spine: MR demonstration

Eosinophilic granuloma commonly involves bone; however, neurologic deficit secondary to bony or extraosseous extension of disease of the spine is rare. We report a case of eosinophilic granuloma of the cervicothoracic junction in a 10-year-old boy and demonstrate the value of magnetic resonance imaging in defining the initial extent of the disease and following the resolution of the extraosseous involvement after therapeutic intervention.

Autoradiographic studies of the gamma-aminobutyric acid (GABA) system in the rat pancreas

The beta-cells of the pancreatic islets have been shown to contain gamma-aminobutyric acid (GABA) together with insulin. Autoradiographic analysis indicated that high affinity GABA binding sites (GABA receptors) are not present in the pancreas. High affinity GABA uptake sites are present, not in beta-cells, but in a few cells on the periphery of the islets. These observations cast doubt on the suggestion that GABA has a paracrine role in the pancreas.

Use of Ar+ plasma etching to localize structural proteins in viruses: studies with adenovirus 2

The experiments described here were undertaken to test the idea that low energy Ar+ plasma etching could be employed as the basis of a method to order viral structural polypeptides according to their physical proximity to the virus surface. Since low energy (500 eV) Ar+ ions do not penetrate deeply into virus surfaces, one expects that the outermost proteins will be damaged before internal ones when intact virions are irradiated. To test this expectation, we exposed adenovirus 2 to a 500-eV Ar+ plasma and then employed sodium dodecyl sulfate-polyacryl-amide gel electrophoresis to assess the extent of damage to the major structural polypeptides. Gel analyses showed that the proteins exposed on the virus surface (proteins II, III, and IV) were degraded rapidly during the first 10 s of irradiation while protein VII, the major core polypeptide, was almost completely protected. Proteins located between the capsid and the core, such as proteins IIIa and VI, were degraded at intermediate rates. Quantitative measurements demonstrated that the observed decay rate differences were not due simply to differences in protein target size; distance to the virion surface made an important contribution. The plasma etching technique, therefore, appears to have considerable potential for the structural analysis of viruses and other macromolecular assemblies where the proximity of individual proteins to the particle surface is unknown.

Effect of galanin on endocrine secretions from the isolated perfused rat stomach and pancreas

Nerves containing galanin immunoreactivity have been shown to be present in the stomach and pancreas. The present experiments were designed to test the effect of galanin on the release of gastric somatostatin-like immunoreactivity (SLI) and immunoreactive gastrin (IR-G), pancreatic SLI and immunoreactive insulin (IR-I) from the isolated perfused rat stomach and pancreas respectively. Galanin (2 X 10(-10)-5 X 10(-8) M) inhibited gastric SLI and IR-G release dose dependently. At a concentration of 10(-8) M, galanin also suppressed IR-I release stimulated by gastric inhibitory polypeptide (2 X 10(-10) M) in the presence of 8.9 X 10(-3) M glucose. Pancreatic SLI release under this condition was not altered. Thus the present study suggests that galanin might be involved in the neural regulation of gastric and pancreatic endocrine secretions.

The effect of total parenteral nutrition (TPN) on gastrin release in the rat

The effect of short-term (7 days) total parenteral nutrition (TPN) on gastrin release was studied in vivo and in the isolated vascularly perfused rat stomach. The daily plasma gastrin concentration of parenterally fed rats was significantly lower than in ad lib fed control animals (53 +/- 17 pg/ml vs 159 +/- 32 pg/ml, P less than 0.05) as early as day 2 and a similar pattern was observed on days 4 and 6. The fasting plasma gastrin concentration of control animals was 2-fold greater than of the parenterally fed group (P less than 0.05). Following oral peptone, the gastrin response of TPN and control animals doubled although peak gastrin levels were greatly reduced in TPN rats. Basal gastrin release from the perfused stomachs of control rats was 2-fold greater than from TPN rats (P less than 0.05). Electrical stimulation of the vagal trunks resulted in a significantly greater elevation in gastrin secretion from control stomachs compared to TPN animals (4-fold vs. 2.4-fold increase, P less than 0.05). Quantification of the antral G-cell population revealed a significant reduction in the number of G-cell of TPN rats compared to controls (97 +/- 8 cells/mm vs 76 +/- 6 cells/mm, P less than 0.05). These results indicate that luminal nutrient stimulation is necessary for the maintenance of normal G-cell secretory activity in vivo and from the in vitro stomach. G-cell hypoplasia appears to be partially responsible for reduced gastrin output to basal and stimulated conditions after TPN.

Chinese hamster ovary cell lysosomes rapidly exchange contents

We have used cell fusion to address the question of whether macromolecules are rapidly exchanged between lysosomes. Donor cell lysosomes were labeled by the long-term internalization of the fluid-phase pinocytic markers, invertase (sucrase), Lucifer Yellow, FITC-conjugated dextran, or Texas red-conjugated dextran. Recipient cells contained lysosomes swollen by long-term internalization of dilute sucrose or marked by an overnight FITC-dextran uptake. Cells were incubated for 1 or 2 h in marker-free media before cell fusion to clear any marker from an endosomal compartment. Recipient cells were infected with vesicular stomatitis virus as a fusogen. Donor and recipient cells were co-cultured for 1 or 2 h and then fused by a brief exposure to pH 5. In all cases, extensive exchange of content between donor and recipient cell lysosomes was observed at 37 degrees C. Incubation of cell syncytia at 17 degrees C blocked lysosome/lysosome exchange, although a "priming" process(es) appeared to occur at 17 degrees C. The kinetics of lysosome/lysosome exchange in fusions between cells containing invertase-positive lysosomes and sucrose-positive lysosomes indicated that lysosome/lysosome exchange was as rapid, if not more rapid, than endosome/lysosome exchange. These experiments suggest that in vivo the lysosome is a rapidly intermixing organellar compartment.

The effects of substance P, histamine and histamine antagonists on somatostatin and gastrin release from the isolated perfused rat stomach

Secretion of somatostatin-like immunoreactivity (SLI) from the isolated perfused rat stomach has been shown to be inhibited by substance P. The present study was initiated to examine the possibility that this action of substance P was mediated via release of histamine. Substance P (1 microM) reduced basal secretion of SLI in agreement with earlier studies. Neither pyrilamine nor cimetidine influenced this action. Basal immunoreactive gastrin (IRG) secretion was unaffected by substance P. Addition of pyrilamine during substance P perfusion increased IRG secretion whereas addition of cimetidine resulted in a delayed decrease on removal of both compounds. Histamine (1 and 10 microM) increased SLI secretion and reduced IRG secretion. Pyrilamine increased and cimetidine decreased IRG secretion but neither drug influenced SLI secretion. Pyrilamine had no effect on histamine-stimulated SLI secretion but inhibition of IRG secretion by histamine was converted to stimulation. Cimetidine potentiated histamine stimulation of SLI secretion and inhibition of IRG secretion.

IN CONCLUSION

(1) substance P inhibition of SLI secretion is unlikely to be mediated via release of histamine. (2) The gastrin cell appears to have both H1- and H2-receptors which mediate opposite actions but H1-receptor-mediated inhibition is predominant. (3) Histamine weakly stimulates SLI secretion but there may be both inhibitory and stimulatory pathways acting via H2- and H1-receptors, respectively.

Neurons of the ventral medulla oblongata that contain both somatostatin and enkephalin immunoreactivities project to nucleus tractus solitarii and spinal cord

The ventral aspect of the medulla oblongata of colchicine-treated rats was examined immunohistochemically using mouse monoclonal antibodies raised against somatostatin (SOM) and rabbit polyclonal antibodies to methionine enkephalin (ENK). Numerous perikarya showed positive immunostaining for both antisera. For the most part, the double-labelled cells were located (1) along the ventrolateral surface in a region that corresponds to nucleus paragigantocellularis, (2) in the region of nucleus gigantocellularis-nucleus raphe magnus and (3) in a discrete area just above the inferior olivary nucleus. In an attempt to determine the projection sites of the SOM/ENK somata, the retrogradely transported fluorescent dye Fluoro-Gold was injected into either the nucleus tractus solitarii (NTS) or the upper part of the thoracic spinal cord. SOM/ENK cells in all 3 regions were labelled by dye administered into the spinal cord whereas only those SOM/ENK cells located in nucleus paragigantocellularis were stained by dye microinjected into NTS. This is the first evidence of a SOM/ENK projection from the ventral medulla to either the spinal cord or NTS.

The effect of muscarinic and beta-adrenergic blockade on cysteamine-induced gastrin secretion by the isolated perfused rat stomach

Cysteamine-induced duodenal ulceration in rats is accompanied by increased circulating gastrin. Although cysteamine appears to exert a direct action on the gastrin cell some groups have provided evidence for an involvement of the autonomic nervous system. The current experiments were performed to determine whether beta-adrenergic or cholinergic (muscarinic) pathways are involved in the acute effect of cysteamine on gastrin secretion in the isolated perfused rat stomach. Cysteamine (1 mM) increased gastrin (IRG) secretion to a maximum ranging between 100% and 192% above basal. A cysteamine concentration of 5mM resulted in peak levels ranging between 150% and 1050% above basal. Addition of atropine or propranalol did not influence the responses obtained. The present results, therefore, do not support a role for either cholinergic or beta-adrenergic pathways in cysteamine-induced gastrin release at the level of the stomach and suggest that in vivo such autonomic effects are mediated extrinsically.