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BK Ca channels modulate cortical astrocytic CO production in newborn pigs
Author(s) -
Xi Qi,
Parfenova Helena,
Jaggar Jonathan H.,
Leffler Charles W.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1023.17
Subject(s) - bk channel , ionomycin , chemistry , channel blocker , calcium , calcium in biology , glutamate receptor , calcium activated potassium channel , calcium imaging , calcium channel blocker , astrocyte , iberiotoxin , potassium channel , biophysics , intracellular , medicine , endocrinology , biology , biochemistry , receptor , central nervous system , organic chemistry
In newborn pigs, we have previously demonstrated that glutamate‐induced cortical astrocytic carbon monoxide (CO) regulates neurovascular coupling by activating large‐conductance calcium‐activated potassium (BK Ca ) channels in arteriolar smooth muscle cells. Recently, BK Ca channels have been also recorded in cortical astrocytes. It is not known whether astrocytic BK Ca channels regulate CO production. Here, we explored the hypothesis that astrocytic CO is fine tuned by BK Ca channels in cortical astrocytes of newborn pigs. Major findings from newborn pig freshly isolated cortical astrocytes and astrocytes in primary culture were: (1) paxilline, a BK Ca channel blocker, increased intracellular calcium concentration ([Ca 2+ ] i ) and elevated CO production; (2) in cortical astrocytes permeabilized with ionomycin, elevation of [Ca 2+ ] i concentration‐dependently increased CO production; and (3) nimodipine, a L‐type calcium channel blocker, blocked glutamate–induced elevations in CO. In summary, this study indicates that [Ca 2+ ] i elevation increases astrocytic CO production. CO activates astrocytic BK Ca channels that inhibit voltage‐dependent Ca 2+ channel activity, causing [Ca 2+ ] i reduction, thereby decreasing CO production.