In this study, the signal cascade transducing carbachol stimulation into c-fos expression in SH-SY5Y neuroblastoma cells was investigated. 1,2-Diacylglycerol formation and c-fos expression were mediated via stimulation of muscarinic M1 receptors and the first 5 min of receptor stimulation were critical for these events. Application of 1,2-dioctanoylglycerol induced c-fos expression and this, as well as carbachol-stimulated c-fos expression, was inhibited by protein kinase C inhibitors. Increasing the intracellular Ca2+ concentration had only small effects on c-fos expression. There was a dependency on extracellular Ca2+ for maximal c-fos expression and 1,2-diacylglycerol formation. The carbachol-stimulated c-fos expression was potentiated by application of the protein phosphatase inhibitor okadaic acid. These results demonstrate the importance of 1,2-diacylglycerol formation for muscarinic receptor-stimulated, protein kinase C-mediated c-fos expression in the SH-SY5Y cells and that this cascade is counteracted by an okadaic acid-sensitive protein phosphatase.

Carbachol↗

PubMed1993

Biosynthesis of corticotropin-releasing hormone in human T-lymphocytes.

Corticotropin-releasing hormone (CRH) is a 41-amino acid neuropeptide which increases the transcription of the proopiomelanocortin (POMC) gene, as well as the biosynthesis and secretion of POMC-derived peptides. Using a specific human CRH radioimmunoassay we have shown that human T-lymphocytes contain immunoreactive CRH. We studied the effects of phytohemagglutinin (PHA) and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the biosynthesis of CRH in human T-lymphocyte cell cultures. A significant increase in CRH mRNA levels was observed in human lymphocytes after 12 h of PHA/TPA treatment, while the levels decreased after 22 h. These findings could imply an immunomodulatory role for CRH that could be due to autocrine and/or paracrine interactions.

Cells, Cultured↗

PubMed1993

Evaluation of ethanol effects on PLC signal transduction pathways using cell lines of neuronal origin.

Human neuroblastoma cells SH-SY5Y and neuroblastoma-glioma cells NG 108-15 have been used as models for the elucidation of the effects of ethanol on receptor-mediated phospholipase C activity, c-fos mRNA expression and protein kinase C activity. Cells were exposed to ethanol (0-200 mM) for varying periods up to seven days. Agonist stimulated events were obtained in NG 108-15 cells with bradykinin and in SH-SY5Y cells with carbachol. Chronic ethanol exposure reduced the agonist-stimulated formation of inositol 1,4,5-trisphosphate in NG 108-15 cells and in SH-SY5Y cells. 100 mM ethanol for seven days increased the membrane bound and cytosolic forms of protein kinase C activity in SH-SY5Y cells. Carbachol (1 mM) induced a maximal c-fos mRNA response after 40 minutes in SH-SY5Y cells, an effect that could be mimicked through protein kinase C stimulation by phorbol esters.

Bradykinin↗

PubMed1992

Nonrelativistic field-theoretic scale anomaly.

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Journal Article↗

PubMed1990

Co-existence of myosin heavy chain I and IIa isoforms in human skeletal muscle fibres with endurance training.

The myosin heavy chain (MHC) composition of single fibres from m. vastus lateralis was analysed by one-dimensional electrophoresis and immunoblotting in three groups of young men with distinct difference in physical activity patterns. No major co-existence of MHC isoforms was found in the group with some daily physical activity. In the very sedentary group, however, 19 +/- 5% (P less than 0.05) of the fibres exhibited coexistence of MHC type IIa and IIb. Further, in the endurance trained group co-existence of MHC type I and IIa was manifested in 36 +/- 4% (P less than 0.05) of the fibres. Disuse and extreme usage of muscle both give rise to an elevation in co-expression of MHC isoforms in single muscle fibres but of markedly different combination of isoforms.

Adult↗