Korean J Physiol Pharmacol.  1997 Oct;1(5):477-484.

Blockade of intrinsic oscillatory activity of cerebellar Purkinje cells by apamin and nickel

• Seo W
• Strahlendorf JC
• Strahlendorf HK

Abstract

Intracellular recordings of oscillatory firing (bursting activity) were obtained from Purkinje cells (PCs) in rat cerebellar slices. Apamin inhibited post-burst hyperpolarizations (PBHs) progressively and finally terminated oscillatory firing activity of PCs. Apamin did not affect the amplitude or duration of the after-hyperpolarization (AHP) between spikes within the burst. In the voltage clamp mode, apamin shifted the whole-cell, quasi-steady state I/V relationship in an inward direction and abolished the zero slope resistance (ZSR) region by blocking outward current. Nickel (Ni2+) terminated oscillatory activity and also abolished the ZSR region. However, Ni2+ did not have progressive blocking action on the post-burst hyperpolarization before it blocked oscillatory activity. Ni2+ blocked an inward current at potentials positive to approximately -65 mV, which was responsible for the ZSR region and outward current at more negative potentials. These data indicated that oscillatory activity of PCs is sustained by a balance between a slow Ni2+ -sensitive inward current and an apamin-sensitive outward current in the region of ZSR of the whole-cell I/V curve.

Keyword

Purkinje cell (PC); Oscillatory firing; Nickel-sensitive inward current; Apamin-sensitive outward current; Zero slope resistance (ZSR) region

MeSH Terms

Animals
Apamin*
Fires
Nickel*
Purkinje Cells*
Rats
Apamin
Nickel