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A dual system of intercellular calcium signaling in glial nets associated with lanceolate sensory endings in rat vibrissae
Author(s) -
TakahashiIwanaga Hiromi,
NioKobayashi Junko,
Habara Yoshiaki,
Furuya Kishio
Publication year - 2008
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.21756
Subject(s) - gap junction , biology , neuroscience , stimulation , mechanoreceptor , schwann cell , fluorescence recovery after photobleaching , axon , microbiology and biotechnology , neuroglia , anatomy , intracellular , central nervous system , biochemistry , membrane
The lanceolate sensory endings that form palisades around the hair follicle associate with networks of branched Schwann cells. To define the properties of these glial networks as possible conduits of Ca 2+ signals, lanceolate endings isolated from rat vibrissae were observed by confocal microscopy while the signaling was locally activated by mechanical stimulation. Intercellular coupling by gap junctions was also assessed by a technique employing fluorescence recovery after photobleaching (FRAP) and by transmission electron microscopy (TEM). Results showed that the glial Ca 2+ signals can spread among the arrays of lanceolates in two forms: rapid signals that originate in individual Schwann processes covering the lanceolate axon terminals around the locus of mechanical stimulation, and delayed ones that travel from the stimulation locus through cytoplasmic arborization of the primarily activated cell to the adjacent cell processes. The former signaling was suppressed by the antipurinergic agents suramin and apyrase, whereas the latter was sensitive to the gap junction blocker carbenoxolon. FRAP experiments and TEM observations corroborated the presence of gap junction communications between the Schwann processes of different cell origins. These findings show that, in the Schwann networks, purinergically induced Ca 2+ signals and those dependent on gap junctions are propagated in their own spatiotemporal patterns to constitute two distinct forms of communication among the mechanoreceptor palisades. J. Comp. Neurol. 510:68–78, 2008. © 2008 Wiley‐Liss, Inc.