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Modulation of calcium currents is eliminated after cleavage of a strategic component of the mammalian secretory apparatus
Author(s) -
Silinsky Eugene M.
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2005.090647
Subject(s) - adenosine , synaptobrevin , calcium , syntaxin , chemistry , free nerve ending , microbiology and biotechnology , biophysics , inhibitory postsynaptic potential , adenosine a1 receptor , secretion , adenosine receptor , medicine , neuroscience , biology , exocytosis , endocrinology , biochemistry , receptor , synaptic vesicle , membrane , vesicle , agonist , organic chemistry
Adenosine inhibits neurotransmitter secretion from motor nerves by an effect on the secretory apparatus in amphibia. In contrast, the inhibitory effect of adenosine is associated with decreases in calcium currents at mouse motor nerve endings. To determine if the action of adenosine in the mouse is mediated thorough a direct effect on calcium channels or through the secretory machinery, the effects of cleavage of the SNARE proteins on the action of adenosine were examined. Cleavage of the SNARE syntaxin with botulinum toxin type C (Botx/C) prevented the inhibitory effect of adenosine on nerve terminal calcium currents. Cleavage of the other SNAREs (synaptobrevin with Botx/D or SNAP‐25 with Botx/A) failed to affect the inhibitory action of adenosine. The results provide evidence for an intimate coupling of nerve terminal calcium channels with a plasma membrane component of the SNARE complex, such that modulation of calcium currents by a G‐protein coupled receptor cannot occur when syntaxin is cleaved.