β-Bungarotoxin inhibits a non-inactivating potassium current in guinea pig dorsal root ganglion neurones

Abstract β-Bungarotoxin (β-BuTx), at concentrations of 0.45–45 nmol/l, selectively reduced a portion of the non-inactivating potassium current (I s k ) in dorsal root ganglion neurones of the guinea pig, measured by voltage clamp of internally perfused cells. The average reduction of I s k obtainable with β-BuTx was 34% and usually not completed within 20 min, but irreversible upon washing for 20 min. The I/V-characteristic of the current blocked by β-BuTx was almost linear. It is suggested that β-BuTx selectively blocks a non-inactivating subtype of potassium channel.