The outward @entity972 current of @entity35 cerebellar granule cells in culture was studied with the whole-cell patch-clamp method. Two voltage-dependent components were identified: a slow current, resembling the classical delayed rectifier current, and a fast component, similar to an IA-type current. The slow current was insensitive to @entity973 and independent of external @entity141 , but significantly inhibited by 3 mM @entity5128 . The fast current was depressed by external @entity973 , with an ED50 = 0.7 mM, and it was abolished by removal of divalent cations from the external medium. The sensitivity of the transient outward current to different divalent cations was investigated by equimolar substitution of @entity141 , @entity3281 and @entity1025 . In 2.8 mM @entity3281 +, the transient @entity972 conductance was comparable to that in 2.8 mM @entity141 , while in 2.8 mM Mg2+ the transient component was drastically reduced, as in the absence of any divalent cations. However, when @entity141 was present, Mg2+ up to 5 mM had no effect. The transient current increased with increasing concentrations of external @entity141 , [ @entity141 ]o, and the maximum conductance vs. [ @entity141 ]o curve could be approximated by a one-site model. In addition, the current recorded with 5.5 mM @entity18650 in the intracellular solution was not different from that recorded in the absence of any @entity141 buffer. These results suggest that divalent cations modulate the @entity972 channel interacting with a site on the external side of the cell membrane.

A transient outward current dependent on external calcium in XXXX cerebellar granule cells.

@entity1025 :: ('CHEBI:18420', 'Chemical') :: ['Mg2+'] @entity5128 :: ('MESH:D019789', 'Chemical') :: ['tetraethylammonium'] @entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca2+'] @entity973 :: ('MESH:D015761', 'Chemical') :: ['4-aminopyridine'] @entity3281 :: ('CHEBI:29035', 'Chemical') :: ['Mn2', 'Mn2+'] @entity18650 :: ('MESH:C025603', 'Chemical') :: ['BAPTA'] @entity972 :: ('MESH:D011188', 'Chemical') :: ['potassium'] @entity35 :: ('10116', 'Species') :: ['rat']
@entity35 :: (10116,Species) :: ['rat']
