ISSN:
1432-1424
Keywords:
Mimosa pudica
;
Pulvinus
;
Protoplast
;
Delayed rectifier potassium current
;
Calcium influx
;
Gadolinium
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Isolated protoplasts from pulvinar motor cells of Mimosa pudica were studied using conventional whole-cell patch clamp techniques. With internal solutions weakly buffered for Ca2+ (0.2 mm EGTA), a run-down of the outward delayed rectifier K+ current was induced by hyperpolarizing the holding potential, and this effect was strongly promoted by high external Ca2+ concentrations. This rundown could be reversed by coming back to less hyperpolarized holding potentials or by lowering the external [Ca2+]. Such rundown was absent when pipette internal solutions strongly buffered (10 mm EGTA) for Ca2+ were used. Ionomycin induced run-down of the K+ current with internal solutions containing 0.2 mm but not 10 mm EGTA. The hyperpolarization-associated rundown was reversibly blocked by Gd3+ and La3+.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00238009
