Appearance of highly sensitive cells to L-type Ca antagonist in cultured cerebellar granule cells.
We studied intracellular Ca2+ ([Ca2+]i) kinetics within single cells using and image-analyzing system. We prepared a culture dish with a bottom made of quartz (non-fluorescent glass) for reducing the background fluorescence during [Ca2+]i measurement. Furthermore, we changed the concentration of the poly-L-lysine solution which had been used to make cells adhere to the dish bottom from the conventional 5 micrograms/ml to 15 micrograms/ml. This modification improved cell viability, prevented colony formation, and therefore, provided favorable cell samples for detection within single cells. Then, we investigated 25 mM KCl-evoked changes in the [Ca2+]i level of rat cerebellar granule cells. We found that sensitivity to KCl was high in some cells but low in others. In a study using the highly sensitive cells, nicardipine, nimodipine and nifedipine were active even at nanomolar or picomolar levels, although their affinities to the L-type Ca ion channel have been reported to act only at micromolar levels.
Taya
K
K
Bayer Yukuhin, Ltd., Miyahara, Osaka, Japan.
Zhang
J
J
Hara
I
I
Watanabe
Y
Y
D000818:Animals; D002118:Calcium / Q000032:analysis / Q000037:antagonists & inhibitors*; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology*; D019044:Image Cytometry; D009529:Nicardipine / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D009553:Nimodipine / Q000494:pharmacology; D011107:Polylysine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D011107:Polylysine; D009553:Nimodipine; D009529:Nicardipine; D009543:Nifedipine; D002118:Calcium