E. Radden et al., A NOVEL METHOD FOR RECORDING WHOLE-CELL AND SINGLE-CHANNEL CURRENTS FROM DIFFERENTIATING CEREBELLAR GRANULE CELLS IN-SITU, Experimental physiology, 79(4), 1994, pp. 495-504
A preparation procedure is described yielding very thin tissue layers
(1-3 cells) of the rat cerebellum. One-week-old rat cerebellum was emb
edded in agarose and cut in 1 mm slices, which then were mounted by a
fresh fibrin preparation on the bottom of a culture dish. After coagul
ation of the fibrin the slice was gently lifted, leaving a thin finger
print-like layer of cells on the bottom of the dish. Individual cells
could be identified by their topographical positions. From these prepa
rations patch-clamp recordings were made of cells in the external and
the internal granule layer and of migrating cells. Whole-cell currents
of cells in the external granule layer, recorded using the perforated
-patch method, show that these neuroblasts already possess a full comp
lement of ionic currents, consisting of a transient sodium current and
a transient and a sustained potassium current. Whereas the potassium
currents are predominant, the maximum sodium peak currents are minute
(42 +/- 5 pA, mean +/- S.E.M., n = 21), i.e. too small for generating
action potentials. There were no significant differences between cells
of the external and the internal granule layer. The ionic channels pa
ssing these currents were identified and characterized in single-chann
el studies on cell-attached patches. Two types of potassium channel we
re found: a non-inactivating channel with a single-channel conductance
of 21 pS and an inactivating channel with a conductance of 6 pS.