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Results for “Nerve Growth Factor”

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At least 19 recordsLinked to original sources
PubMed1976

alpha-Adrenergic regulation of secretion of mouse saliva rich in nerve growth factor.

Nerve growth factor has been quantified by both bioassay and radial immunodiffusion in mouse saliva elicited by several secretagogues. The concentrations by bioassay of nerve growth factor in both epinephrine- and norepinephrine-induced saliva (3400 and 900 mug/ml, respectively) are higher than reported in any other source. In contrast, the concentrations of nerve growth factor in isoproterenol- and pilocarpine-induced saliva are relatively low (17 and 2 mug/ml, respectively). The specific activity of the salivary nerve growth factor was 41, 36, 2, and 0.6 mug/mg of protein in secretions elicited by epinephrine, norepinephrine, pilocarpine, and isoproterenol, respectively. Salivation after administration of either epinephrine or norepinephrine was completely inhibited by the alpha-adrenergic blocker, phenoxybenzamine. These results suggest that the release of saliva rich in nerve growth factor is primarily regulated through alpha-adrenergic receptors.

Animals↗
PubMed1977

Alteration of cellular adhesion by nerve growth factor.

Nerve growth factor increases the initial rates of cell-substratum and cell-cell adhesion of sympathetic nerve cell clone PC12. It also stimulates adenosine 3':5'-cyclic monophosphate accumulation in the cells, and exogenous adenosine 3':5'-cyclic monophosphate increases cell-substratum adhesion. NGH-stimulated adhesion is energy dependent and cold-sensitive and does not require de novo protein synthesis. It is probably mediated by an effect of adenosine 3':5'-cyclic monophosphate on the plasma membrane. Stimulation of cellular adhesion may be the first step in NGF-initiated neurite outgrowth by sympathetic nerve cells.

Bucladesine↗
PubMed1979

Stimulation of the pituitary-adrenocortical axis by nerve growth factor.

Nerve growth factor (NGF) is a protein essential for the development and maintenance of the peripheral sympathetic nervous system, causing responsive neurones to increase in size and to extend neurites. Biochemically, the selective induction of tyrosine hydroxylase (TH) and dopamine beta-hydroxylase key enzymes in catecholamine biosynthesis is one of its most characteristic effects. Both the morphological and biochemical effects are modulated by glucocorticoids, suggesting a close relationship between specific effects of NGF and hormone action. NGF has been shown to induce an increase in adrenal cyclic AMP in intact but not in hypophysectomised rats, and so we have looked directly at the effect of systemic administration of NGF on the hypothalamo-pituitary-adrenal axis. We report here that NGF induced an enhanced secretion of adrenocorticotropin (ACTH) and a prolonged increase in plasma glucocorticoid concentration after intravenous (i.v.) injection. Such effects could have important implications for the biological activity of NGF.

Adrenocorticotropic Hormone↗
PubMed1979

Human melanoma cells have both nerve growth factor and nerve growth factor-specific receptors on their cell surfaces.

Human melanoma cells were examined in an indirect membrane immunofluorescence assay for surface nerve growth factor (NGF) and NGF receptors. This assay revealed that human melanoma cells have various levels of NGF and NGF receptors on the plasma membrane, whereas a variety of human sarcoma and carcinoma tumor cells and normal human fibroblasts are negative. Surface NGF could be detected on melanoma cells with a rabbit antiserum directed to NGF at titers as high as 1:64; prior adsorption of this antibody with mouse 2.5S NGF resulted in a loss of fluorescence. The melanoma cells were positive whether or not they were grown in the presence of fetal calf serum. NGF production by human melanomas is a previously unrecognized property of this differentiated cell type. Although other cells in culture have been shown to produce NGF, the association of NGF production with the presence of NGF receptors on the cell surface is rare among tumor cells, and may represent an opportunity for "autostimulation" of melanoma cells by this growth factor.

Cell Line↗
PubMed1977

A tryptic digestion fragment of nerve growth factor with nerve growth promoting activity.

A peptide, isolated from the acid-insoluble portion of a tryptic digest of cyanogen bromide cleaved nerve growth factor, favors life maintenance of sensory target cells and promotes rapid neurite outgrowth from 7-day-old chick embryo sensory ganglia. The fragment has been identified as a 30 amino acid peptide consisting of two linear oligopeptides linked by a disulphide bridge and corresponding to residues 10-25 and 75-88 of the amino acid sequence of nerve growth factor. On a molar basis the fragment is about 100 times more effective than intact nerve growth factor. Other peptides isolated from the digest are biologically inactive.

Amino Acids↗
PubMed1978

Evaluation of the effects of nerve growth factor and anti-nerve growth factor on the development of central catecholamine-containing neurons.

Intracisternal NGF or anti-NGF has been found to produce no long-term major alterations in central norepinephrine (NE) or dopamine levels when administered to neonatal rats. While NGF and anti-NGF were found to produce significant changes in brain NE content within one week of treatment, changes in central NE were no longer detectable at 30 days of age. Modification of the growth response of the central adrenergic neurons following 6-OHDA treatment was also not affected by NGF or anti-NGF when evaluated 3 weeks after treatment. However, centrally administered anti-NGF did induce a loss of peripheral NE terminals, which was attributed to leakage of the anti-NGF from the central injection site.

Adrenergic Fibers↗
PubMed1977

Evidence for pro-beta-nerve growth factor, a biosynthetic precursor to beta-nerve growth factor.

The biosynthesis of beta-nerve growth factor (betaNGF) was studied in mouse submaxillary glands incubated with L-[(35)S]cystine. betaNGF was isolated from tissue extracts by the addition of antiserum against betaNGF and the washed immunoprecipitates were analyzed by sodium dodecyl sulfate gel electrophoresis. With short labeling periods (10 and 25 min) there is a major labeled species with an apparent molecular weight of 22,000 and a smaller peak comigrating with purified betaNGF chains (13,260). As time proceeds, the radioactivity in the 22,000 molecular weight peak plateaus, while the label in betaNGF continues to increase, until by 4 hr it greatly exceeds the radioactivity of the 22,000 molecular weight species. When glands incubated for 10 min are transferred to medium containing a large excess of unlabeled L-cystine, the 22,000 molecular weight peak gradually declines, and there is a corresponding increase in radioactivity at the betaNGF position. The 22,000 molecular weight species isolated from sodium dodecyl sulfate gels possesses all the cystine-containing peptides of betaNGF, and possibly two additional ones. When immunoprecipitates from submaxillary glands labeled for 25 min are incubated with the gamma subunit (a specific arginyl-esteropeptidase associated with betaNGF in the 7S NGF complex), the radioactivity in the 22,000 molecular weight species is converted to the betaNGF position. The results suggest that the 22,000 molecular weight species is a biosynthetic precursor to betaNGF, and that the gamma subunit may function as a specific protease in the processing event.

Animals↗
PubMed1979

Rapid, sequential changes in surface morphology of PC12 pheochromocytoma cells in response to nerve growth factor.

The effect of nerve growth factor (NGF), a substance that promotes the differentiation and maintenance of certain neurons, was studied via scanning electron microscopy utilizing the PC12 clonal NGF-responsive pheochromocytoma cell line. After 2-4 d of exposure to NGF, these cells acquire many of the properties of normal sympathic neurons. However, by phase microscopy, no changes are discernible within the first 12-18 h. Since the primary NGF receptor appears to be a membrane receptor, it seemed likely that some of the initial responses to the factor may be surface related. PC12 cells maintained without NGF are round to ovoid and have numerous microvilli and small blebs. After the addition of NGF, there is a rapidly initiated sequential change in the cell surface. Ruffles appear over the dorsal surface of the cells with 1 min, become prominent by 3 min, and almost disappear by 7 min. Microvilli, conversely, disappear as the dorsal ruffles become prominent. Ruffles are seen at the the periphery of cell at 3 min, are prominent on most of the cells by 7 min and are gone by 15 min. The surface remains smooth from 15 min until 45 min when large blebs appear. The large blebs are present on most cells at 2 h and are gone by 4 h. The surface remains relatively smooth until 6-7 h of NGF treatment, when microvilli reappear as small knobs. These microvilli increase in both number and length to cover the cell surface by 10 h. These changes were not observed with other basic proteins, with alpha-bungarotoxin (which binds specifically to PC12 membranes), and were not affected by an RNA synthesis inhibitor that blocks initiation of neurite outgrowth. Changes in the cell surface architecture appear to be among the earlist NGF responses yet detected and may represent or reflect primary events in the mechanism of the factor's action.

Animals↗
PubMed1976

Molecular size of nerve growth factor in dilute solution.

Nerve growth factor (NGF) is a protein composed of two identical chains of mass 13,259. An analysis of the sedimentation equilibrium, sedimentation velocity, and gel filtration behavior of dilute solutions of NGF indicates the existence of a rapidly reversible monomer in equilibrium dimer equilibrium and that the association constant K for the reaction at neutral pH is 9.4 X 10(6)M-1. Reaction mixtures consist of equal concentrations of monomer and dimer at a total protein concentration as high as 1.4 mug/ml, and at 1 ng/ml, monomer accounts for greater than 99% of the total. The latter concentration is 20 to 30 times that required for the biological activity of NGF. Several lines of evidence suggest that the dimerization reaction is highly stereospecific, although its biological significance is not known.

Animals↗
PubMed1978

Isolation of human nerve growth factor from placental tissue.

Nerve growth factor (NGF) has been isolated from human placental tissue. Using the chicken embryo dorsal root ganglia assay, we determined levels of NGF activity for the amnion, placental cotyledons, cord serum, fetal serum, and maternal serum. The highest levels of NGF activity were measured in placental cotyledons. After homogenization and centrifugation of the placental cotyledons, the supernatant was sequentially chromatographed, at neutral pH, on Sephadex G-100, DEAE-11, and Sephadex G-150. A high-molecular-weight protein fraction (approximately 150,000), which contained all the biological activity, was isolated in this fashion. Analytical isoelectric focusing of this fraction revealed a basic protein component (pI 9.5) of the high-molecular-weight species. Assays for NGF activity of all protein components separated by analytical isoelectric focusing showed that NGF activity was associated only with the basic protein component. Correspondingly, preparative isoelectric focusing of the high-molecular-weight species yielded a basic protein with very high biological activity (1-3 ng per biological unit) that was immunochemically active against rabbit IgG made against mouse beta-NGF.

Animals↗
PubMed1979

Modulation of protein synthesis by nerve growth factor.

The effects of nerve growth factor (NGF) and two analogs of cAMP have been studied in the PC12 line of rat pheochromocytoma cells. We have used two-dimensional gel electrophoresis to detect more than 800 proteins from control and NGF-treated cells. Of these proteins, none were qualitatively repressed in response to NGF, and no new proteins appeared after NGF treatment. Visual inspection of the gels showed that approximately 5% of the proteins were detectably increased or decreased in rate of synthesis by NGF, and each of these changes was mimicked by both cAMP analogs. The two-dimensional gel data were further analyzed by a computerized scanning system. This analysis has revealed many significant changes that are smaller than those detected by eye. Approximately 25 to 30% of the proteins analyzed were found to be altered in rate of synthesis by 30% or more. Statistical analysis has shown that the response to NGF and the response to dibutyryl cAMP are highly correlated, even down to changes as small as 30%. No proteins were found to be significantly altered by both dibutyryl cAMP and 8-bromo cAMP, but not by NGF. These results show that NGF causes only quantitative modulations of protein synthesis in PC12 cells, and these data strongly suggest that the response of PC12 cells to NGF is mediated by cAMP.

Animals↗
PubMed1978

Purification and characterization of nerve growth factor from the venom of Bungarus multicinctus.

The nerve growth factor from Bungarus multicinctus venom was purified by means of successive chromatography on Sephadex G-50, carboxymethyl-cellulose, carboxymethyl-Sephadex C-50 and Sephadex G-50. The purified nerve growth factor was homogeneous by polyacrylamide disc gel electrophoresis. The molecular weight was estimated to be about 21 000 by gel filtration. Compared with the nerve growth factors from the venoms of other Elapidae, namely Naja naja and Naja naja atra, this protein showed high isoelectric point of approximately pH 10. A characteristic of the nerve growth factor of B. multicinctus venom is that the protein consisted of two subunits of equal molecular weight which are linked covalently to each other by a disulfide bridge. The purified B. multicintus nerve growth factor elicited its maximal neurite outgrowth from embryonic dorsal root ganglia at the concentration interval from 30 to 100 ng/ml.

Amino Acids↗