Neuroligand-mediated calcium signaling in cultured human schwannoma cells.
Intracellular Ca2+ release regulates proliferation of nonexcitable cells, however, it is not known whether and which neuroligands modulate the free intracellular Ca2+ concentration in human schwannoma cells. Confocal laser scanning microscopy was used for the study of neuroligand-induced Ca2+ signaling in cultured human schwannoma cells loaded with the Ca2+-sensitive fluorescent dyes Calcium Green-1 and Fura Red. Intracellular Ca2+ transients were observed during bath application of ATP (90% of cells tested), endothelin (60%), and norepinephrine (20%); histamine, serotonin, glutamate, and bradykinin did not have this effect. Two types of P2Y nucleotide receptor subtypes involved in ATP-induced Ca2+ transients could be separated by application of different P2Y receptor agonists and cross desensitization experiments: P2Y1 (rank order of potency: 2-MeSADP > 2-MeSATP > ADP > ATP) and P2Y2 (sensitive to UTP and ATP). Endothelin-induced Ca2+ signaling was also seen during application of [Ala(1,3,11,15)]ET-1; this suggests the presence of an ET(B) receptor subtype. The results indicate that the presence of receptors linked to neuroligand-triggered Ca2+ signaling does not seem to be abnormal in a human Schwann cell tumor, i.e. schwannoma cells retain this characteristic of peripheral glia.
Mayer
C
C
Department of Physiology, University of Munich, Germany.
Kamleiter
M
M
Sanchez-Brandelik
R
R
Rosenbaum
C
C
Kluwe
L
L
Hanemann
C O
CO
Grafe
P
P
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000502:physiology; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002455:Cell Division; D019333:Endothelin-2 / Q000494:pharmacology; D005456:Fluorescent Dyes; D018698:Glutamic Acid / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D018613:Microscopy, Confocal; D009442:Neurilemmoma / Q000473:pathology / Q000503:physiopathology*; D016518:Neurofibromatosis 2 / Q000473:pathology / Q000503:physiopathology*; D009638:Norepinephrine / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D014407:Tumor Cells, Cultured
D019333:Endothelin-2; D005456:Fluorescent Dyes; D012701:Serotonin; D018698:Glutamic Acid; D000244:Adenosine Diphosphate; D006632:Histamine; D000255:Adenosine Triphosphate; D001920:Bradykinin; D002118:Calcium; D009638:Norepinephrine