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.
Green
K N
KN
Institute for Cardiovascular Research, University of Leeds, LS2 9JT, Leeds, UK.
Taylor
S C
SC
Smith
I F
IF
Peers
C
C
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