Increase of intracellular Ca2+ by adenine and uracil nucleotides in human midbrain-derived neuronal progenitor cells.
Nucleotides play an important role in brain development and may exert their action via ligand-gated cationic channels or G protein-coupled receptors. Patch-clamp measurements indicated that in contrast to AMPA, ATP did not induce membrane currents in human midbrain derived neuronal progenitor cells (hmNPCs). Various nucleotide agonists concentration-dependently increased [Ca(2+)](i) as measured by the Fura-2 method, with the rank order of potency ATP>ADP>UTP>UDP. A Ca(2+)-free external medium moderately decreased, whereas a depletion of the intracellular Ca(2+) storage sites by cyclopiazonic acid markedly depressed the [Ca(2+)](i) transients induced by either ATP or UTP. Further, the P2Y(1) receptor antagonistic PPADS and MRS 2179, as well as the nucleotide catalyzing enzyme apyrase, allmost abolished the effects of these two nucleotides. However, the P2Y(1,2,12) antagonistic suramin only slightly blocked the action of ATP, but strongly inhibited that of UTP. In agreement with this finding, UTP evoked the release of ATP from hmNPCs in a suramin-, but not PPADS-sensitive manner. Immunocytochemistry indicated the co-localization of P2Y(1,2,4)-immunoreactivities (IR) with nestin-IR at these cells. In conclusion, UTP may induce the release of ATP from hmNPCs via P2Y(2) receptor-activation and thereby causes [Ca(2+)](i) transients by stimulating a P2Y(1)-like receptor.
Rubini
Patrizia
P
Rudolf-Boehm-Institute for Pharmacology und Toxicology, Haertelstrasse 16-18, University of Leipzig, D-04107 Leipzig, Germany.
Milosevic
Javorina
J
Engelhardt
Johannes
J
Al-Khrasani
Mahmoud
M
Franke
Heike
H
Heinrich
Attilla
A
Sperlagh
Beata
B
Schwarz
Sigrid C
SC
Schwarz
Johannes
J
Nörenberg
Wolfgang
W
Illes
Peter
P
D000227:Adenine Nucleotides / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D049109:Cell Proliferation; D002478:Cells, Cultured; D006801:Humans; D007381:Intermediate Filament Proteins / Q000378:metabolism; D008636:Mesencephalon / Q000166:cytology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D064231:Nestin; D055495:Neurogenesis / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D018408:Patch-Clamp Techniques; D058910:Purinergic P2 Receptor Agonists; D018048:Receptors, Purinergic P2 / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D014500:Uracil Nucleotides / Q000378:metabolism*
D000227:Adenine Nucleotides; D007381:Intermediate Filament Proteins; C577484:NES protein, human; D009419:Nerve Tissue Proteins; D064231:Nestin; D058910:Purinergic P2 Receptor Agonists; D018048:Receptors, Purinergic P2; D014500:Uracil Nucleotides; D002118:Calcium