C. Pascarel et al., DIFFERENT EFFECTS OF GADOLINIUM ON I-KR, I-KS AND I-K1 IN GUINEA-PIG ISOLATED VENTRICULAR MYOCYTES, British Journal of Pharmacology, 124(2), 1998, pp. 356-360
1 Using the whole cell configuration of the patch clamp technique, we
studied the potential blocking effects of gadolinium (1 mu M to 1 mM)
on potassium currents: I-KR, I-KS and I-K1. The study was performed on
guinea-pig isolated ventricular myocytes. 2 The background current, I
-K1 was insensitive to Gd3+. Thus, we found that no obvious screening
of surface charges was visible with concentrations of Gd3+ up to 100 m
u M. 3 By use of three different protocols: tail currents fitting, ana
lysis of envelope of tails and electrophysiological dissection, we fou
nd that I-KR was the only component of I-K that was sensitive to Gd3+.
The sensitivity was apparently different depending on the protocol us
ed. 4 Comparison of the results obtained with the different protocols
revealed that the rapid component of I-KR is more sensitive to Gd3+ th
an the slow one. 5 Of the different protocols used to distinguish betw
een I-KR and I-KS, the electrophysiological dissection seems to be the
more accurate.