Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of galanin (7-70 nM) on ATP-sensitive K+ channels (KATP channels), membrane potential and the release of insulin have been studied in the insulinoma cell line, RINm5F. Single-channel currents have been recorded from excised outside-out membrane patches as well as intact insulin-secreting cells and it is shown that galanin, added to the outside of the membrane, specifically activates KATP channels. Studies carried out using the fluorescent probe bisoxonol demonstrate that galanin hyperpolarizes RINm5F cells. Galanin was also found to abolish glyceraldehyde-stimulated immunoreactive insulin release from the insulinoma cells. Both the galanin-evoked hyperpolarization and inhibition of insulin release were abolished in cells pre-exposed to pertussis toxin. The possibility that the gating of KATP channels could be mediated by a G-protein was studied in patch-clamp experiments by adding F- to the solution bathing the inside of the cell membranes (open-cell), in order to generate the alumino-fluoride complex AlF4-. F- (1-10 mM) evoked dose-dependent activation of KATP channels and this effect was fully reversible. F- was also able to activate K+ channels inhibited by ATP. That the fluoride activation of KATP channels is mediated by the complex AlF4- was indicated by experiments in which AlCl3 (10 microM) was found to enhance further the activation of K+ channels evoked by 1 mM F- and by results showing that F(-)-stimulation of KATP channels was (i) abolished in the continued presence of F- by the Al3+ chelator deferoxamine (0.5 mM) and (ii) could be mimicked by VO4(3-) which has a structure similar to that of the AlF4- complex.
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PMID:Galanin activates nucleotide-dependent K+ channels in insulin-secreting cells via a pertussis toxin-sensitive G-protein. 247 May 86

Endothelins (ETs) promote cytoskeletal actin reorganization of cultured astrocytes (Koyama and Baba, Neuroscience 61:1007-1016, 1994; Koyama and Baba, Glia 16:342-350, 1996). In this study, we examined the signal transduction involved in that activity of ETs. Immunoblot analysis with an anti-phosphotyrosine antibody showed that ET-3 (1 nM) increased tyrosine phosphorylation of 120 Kda and 70 Kda astrocytic proteins. The tyrosine phosphorylations of both proteins reached a maximum at 1 nM ET-3. In morphological examinations, ET-3 (1 nM) induced stress fibers, an organized F-actin structure, and focal adhesions in 0.5 mM dibutyryl cAMP (DBcAMP)-treated astrocytes within 30 min. Immunochemical staining of phosphotyrosine revealed that the newly formed focal adhesions possessed phosphotyrosine immunoreactivity. Phorbol 12-myristate 13 acetate (PMA, 100 nM), bradykinin (1 microM), angiotensin II (100 nM), and A23187 (5 microM) did not induce astrocytic stress fibers and had no obvious effects on tyrosine phosphorylation of 120 Kda and 70 Kda proteins. Tyrosine phosphorylation of astrocytic 120 Kda and 70 Kda proteins was stimulated by 1 mM sodium orthovanadate (VO4(3-)), a protein tyrosine phosphatase inhibitor. VO4(3-) promoted reorganization of stress fibers and focal adhesions in DBcAMP-treated astrocytes. Neither chelation of intra- and extracellular Ca2+ nor pre-treatment with pertussis toxin (PTX) affected the ET-induced tyrosine phosphorylation and stress fiber formation in cultured astrocytes. These results suggest a relationship between cytoskeletal actin reorganization and the tyrosine phosphorylation of astrocytic proteins by ETs.
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PMID:Endothelin-induced protein tyrosine phosphorylation of cultured astrocytes: its relationship to cytoskeletal actin organization. 1038 51