Influence of integrin-blocking peptide on gadolinium- and hypertonic shrinking-induced neurotransmitter release in rat brain synaptosomes.
Polyvalent cations and hypertonic shrinking of presynaptic endings lead to calcium-independent exocytosis in various synapses. In the present study we have investigated the contribution of integrins to this phenomenon. It was found that hypertonic shrinking, polyvalent cations ruthenium red and gadolinium results in dose-dependent calcium-independent neurotransmitter release in rat brain synaptosomes. The exocytotic mechanism of neurotransmitter release induced by 300 microM gadolinium was additionally verified by the fluorescent dye FM2-10. We found that 200 microM of RGDS peptide, an inhibitor of integrins, decreased polyvalent gadolinium-induced [3H]D: -aspartate release by 26%. This compound had no effect upon hypertonicity-induced release. The peptide RGES, a negative control for RGDS; genistein, an inhibitor of tyrosine kinases; and citrate, an inhibitor of lanthanides-induced aggregation were ineffective in both cases. Therefore, we have shown that integrins did not influence hypertonicity-evoked [3H]D: -aspartate release, but partially mediated that evoked by gadolinium ions.
Waseem
Tatyana V
TV
Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, Minsk 220072, Belarus.
Lapatsina
Liudmila P
LP
Fedorovich
Sergei V
SV
D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001923:Brain Chemistry / Q000187:drug effects; D002412:Cations / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005089:Exocytosis / Q000187:drug effects; D005456:Fluorescent Dyes; D005682:Gadolinium / Q000494:pharmacology*; D006982:Hypertonic Solutions / Q000494:pharmacology*; D016023:Integrins / Q000037:antagonists & inhibitors*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology*; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D051381:Rats; D017208:Rats, Wistar; D013395:Sucrose / Q000494:pharmacology; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D002412:Cations; C086686:FM2 10; D005456:Fluorescent Dyes; D006982:Hypertonic Solutions; D016023:Integrins; D009419:Nerve Tissue Proteins; D018377:Neurotransmitter Agents; D009842:Oligopeptides; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D001224:Aspartic Acid; D005680:gamma-Aminobutyric Acid; D013395:Sucrose; C046617:arginyl-glycyl-aspartyl-serine; D005682:Gadolinium