Intracellular calcium transients mediated by P2 receptors in the paranodal Schwann cell region of myelinated rat spinal root axons.
Receptors for neuroligands in the paranodal Schwann cell region of a myelinated nerve fiber could have important functions. We have used confocal laser scanning microscopy in combination with Ca(2+)-sensitive fluorescent dyes to study the possible effects of purinergic agonists on the free intracellular calcium concentration ([Ca2+]i) in paranodes of isolated rat spinal roots. Application of ATP in concentrations of 100 and 300 microM resulted in a transient rise in [Ca2+]i in about 57% of the paranodal Schwann cell regions studied. UTP was equipotent to ATP whereas adenosine, beta,gamma-methylene ATP, and elevation of the extracellular K+ concentration by 10 mM had no effect on [Ca2+]i. These data indicate the presence of the P2Y2 (previously termed P2U) subtype of P2 receptors in the paranodal Schwann cell membrane of rat spinal root myelinated nerve fibers.
Mayer
C
C
Department of Physiology, University of Munich, Germany.
Wächtler
J
J
Kamleiter
M
M
Grafe
P
P
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001369:Axons / Q000378:metabolism*; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D005456:Fluorescent Dyes; D007093:Imidazoles; D007425:Intracellular Membranes / Q000378:metabolism*; D008297:Male; D018613:Microscopy, Confocal; D009413:Nerve Fibers, Myelinated / Q000378:metabolism*; D009930:Organic Chemicals; D051381:Rats; D017208:Rats, Wistar; D011983:Receptors, Purinergic / Q000502:physiology*; D012583:Schwann Cells / Q000378:metabolism*; D013126:Spinal Nerve Roots / Q000378:metabolism* / Q000648:ultrastructure; D014544:Uridine Triphosphate / Q000494:pharmacology
D001572:Benzofurans; D005456:Fluorescent Dyes; D007093:Imidazoles; D009930:Organic Chemicals; D011983:Receptors, Purinergic; C071336:calcium green; C082877:fura red; D000255:Adenosine Triphosphate; D002118:Calcium; D014544:Uridine Triphosphate