Differential coupling of voltage-gated Ca(2+) channels to catecholamine secretion from separate PC12 cell batches.
Amperometric recordings were employed to investigate the coupling of Ca(2+) channels to catecholamine secretion in two batches of pheochromocytoma (PC12) cells. In 'new' (freshly obtained) cells (PC12n cells), secretion was dependent on Ca(2+) influx through L-type and N-type Ca(2+) channels. By contrast, in 'aged' cells (maintained in liquid nitrogen for 6-8 years; PC12a cells), secretion was mostly dependent on Ca(2+) influx through N-type channels. Patch clamp recordings revealed that L-type channels accounted for only ca. 26% of total whole-cell current in PC12a cells (determined by blockade caused by 2 microM nifedipine). In contrast, nifedipine suppressed currents by ca. 59% in PC12n cells. Thus important differences in fundamental physiological properties can be observed in PC12 cell batches even when obtained from the same source and maintained under identical conditions.
Institute for Cardiovascular Research, University of Leeds, LS2 9JT, Leeds, UK.
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Green
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Taylor
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Smith
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Peers
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology; D020746:Calcium Channels, L-Type / Q000502:physiology*; D020864:Calcium Channels, N-Type / Q000502:physiology*; D002395:Catecholamines / Q000378:metabolism*; D005089:Exocytosis / Q000502:physiology*; D016716:PC12 Cells; D051381:Rats
D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D020864:Calcium Channels, N-Type; D002395:Catecholamines; D002118:Calcium