Participation of low-threshold Ca2+ spike in the Purkinje cells complex spike

In Purkinje cells from cerebellar slice cultures, low-threshold Ca2+ spike (LTS) gives rise to complex bursts in the soma that resemble the complex spike induced by climbing fibers stimulation.We show that LTS is reduced by T-type and R-type Ca2+ channel blockers (SNX-482, nickel, or mibefradil).We propose that LTS is generated by openings of T-type Ca2+ channels (alpha-IG and/or alpha-II subunits) and R-type Ca2+ channels (alpha-IE subunit isoforms with a weak sensitivity to SNX-482 and to nickel). Using mibefradil we show that climbing fiber stimulation activates LTS, which contributes to the shape of the response. This Ca2+ entry may be involved in Ca2+ -dependent synaptic plasticity of the parallel fiber input induced by climbing fiber activation.