G. James et Am. Butt, Adenosine 5 ' triphosphate evoked mobilization of intracellular calcium incentral nervous system white matter of adult mouse optic nerve, NEUROSCI L, 268(1), 1999, pp. 53-56
Although it has been established that immature glial cells express function
al purinergic receptors, the responsiveness of mature glial cells in vivo h
ad not been elucidated. This question was addressed using fura-2 ratiometri
c measurements of [Ca2+](i) in the adult mouse optic nerve, a central nervo
us system (CNS) white matter tract, taking advantage of the facts that (i),
the optic nerve contains glial cells but not neurons and (ii), that fura-2
loads primarily astrocytes in isolated intact optic nerves. We show that a
denosine 5' triphosphate (ATP) evoked an increase in [Ca2+](i) in a concent
ration-dependent manner with a half-maximal effect at 3 mu m ATP, and with
a rank order of agonist potency of ATP > ADP > alpha,beta-methyline-ATP > U
DP > adenosine. The results indicate mainly P-2Y and P-2X components, consi
stent with the in vitro astroglial purinergic receptor profile. The in vivo
response of mature glia to ATP may be important in their response to CNS d
amage. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.