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The effect of polyamines on K ATP channels in guinea‐pig ventricular myocytes
Author(s) -
Niu X. W.,
Meech R. W.
Publication year - 1998
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1998.401bq.x
Subject(s) - spermine , membrane potential , biophysics , spermidine , myocyte , chemistry , putrescine , polyamine , gating , potassium channel , ion channel , intracellular , biochemistry , endocrinology , biology , enzyme , receptor
1 The effect of natural polyamines on K ATP channels was studied using inside‐out patches from guinea‐pig ventricular myocytes. 2 At a holding potential of +40 mV, spermine at the intracellular membrane surface reduced the K ATP channel open probability ( P open ) in a dose‐dependent manner. Half‐maximal inhibition occurred at 29 μM with a Hill coefficient of 1.2. 3 The effect of spermine on P open was not greatly influenced by the membrane potential but there appeared to be a small reduction in unitary current amplitude during strong depolarizations. 4 Analysis of K ATP single channel kinetics showed that spermine inhibited the channel by decreasing the mean open time and introducing transitions to a long closed state. 5 Spermidine (0.1 mM) was found to have a similar effect to spermine. Putrescine (10 mM) was found to block more effectively at positive membrane potentials. Up to 20 mM arginine had no significant effect on K ATP channels. 6 Our results indicate that natural polyamines influence native K ATP channel gating in cardiac myocytes.