Premium
Selective Changes in Cell Bodies and Growth Cones of Nerve Growth Factor‐Differentiated PC12 Cells Induced by Chemical Hypoxia
Author(s) -
Gibson Gary,
ToralBarza Lourdes,
Zhang Hui
Publication year - 1997
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1997.69020603.x
Subject(s) - depolarization , channel blocker , hypoxia (environmental) , nifedipine , intracellular , cell growth , chemistry , cell , growth cone , biophysics , microbiology and biotechnology , cytosol , medicine , endocrinology , biology , calcium , biochemistry , oxygen , axon , enzyme , organic chemistry
Cytosolic free Ca 2+ concentration ([Ca 2+ ] i ) was measured in differentiated PC12 cells to test whether chemical hypoxia selectively alters intracellular Ca 2+ in growth cones and cell bodies. Hypoxia increased [Ca 2+ ] i and exaggerated its response to K + depolarization in both parts of the cells. [Ca 2+ ] i in the cell bodies was greater than that in the growth cones under resting conditions and in response to K + or hypoxia. Ca 2+ ‐channel blockers selectively altered these responses. The L‐channel blocker nifedipine reduced [Ca 2+ ] i following K + depolarization by 67% in the cell bodies but only 25% in the growth cones. In contrast, the N‐channel blocker ω‐conotoxin GVIA (ω‐CgTX) diminished K + ‐induced changes in [Ca 2+ ] i only in the growth cones. During hypoxia, nifedipine was more effective in the cell bodies than in the growth cones. During hypoxia, ω‐CgTX diminished K + ‐induced changes by 50–75% in both parts of the cell, but only immediately after depolarization. The combination of nifedipine and ω‐CgTX diminished the [Ca 2+ ] i response to K + with or without hypoxia by >90% in the cell body and 70% in the growth cones. Thus, the increased Ca 2+ entry with K + during hypoxia is primarily through L channels in the cell bodies, whereas in growth cones influx through L and N channels is about equal. The results show that chemical hypoxia selectively alters Ca 2+ regulation in the growth cone and cell body of the same cell.