Adenosine 5'-triphosphate-evoked calcium responses in terminal Schwann cells of lanceolate sensory endings isolated from rat vibrissae.
Extracellular adenosine 5'-triphosphate (ATP) has been known to mediate and modulate cutaneous sensations. We examined the effect of this substance on isolated terminal Schwann cells associating with lanceolate endings, the mechanoreceptors of rat vibrissae. The free intracellular calcium concentration ([Ca(2+)](i)) of the sensory device was monitored by digital image microscopy in combination with a calcium-sensitive fluorescent probe, Fura-2. Application of ATP in concentrations raging from 10 microM to 1 mM evoked an increase in [Ca(2+)](i) in Schwann cell processes covering the lancet-like axon terminals as well as in round perikarya of the cells protruding from the terminals. In both portions, the ATP-evoked [Ca(2+)](i) elevations were slowly oscillatory at 10 and 20 microM, and continuous at concentrations higher than 50 microM. Suramin 100 microM blocked the effect of ATP. Uridine 5'-triphosphate was equipotent with ATP, while ,alpha,beta-methylene ATP was ineffective. These data indicate that the terminal Schwann cells express P2Y purinoceptors linked with the intracellular Ca(2+) signaling, and that this phenomenon is involved in the ATP-mediated sensory modulation.
Takahashi-Iwanaga
Hiromi
H
Department of Anatomy, Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Sapporo 060-8638, Japan. hiromiva@med.hokudai.ac.jp
Habara
Yoshiaki
Y
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008465:Mechanoreceptors / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000378:metabolism; D058472:Receptors, Purinergic P2Y1; D009418:S100 Proteins / Q000378:metabolism; D012583:Schwann Cells / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013498:Suramin / Q000494:pharmacology; D014110:Touch / Q000187:drug effects / Q000502:physiology; D014544:Uridine Triphosphate / Q000494:pharmacology; D014738:Vibrissae / Q000294:innervation* / Q000502:physiology
D005456:Fluorescent Dyes; C546384:P2ry1 protein, rat; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D009418:S100 Proteins; D013498:Suramin; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D002118:Calcium; D014544:Uridine Triphosphate