Blockade of intrinsic oscillatory activity of cerebellar Purkinje cells by apamin and nickel.
- Author:
Whasook SEO
1
;
Jean C STRAHLENDORF
;
Howard K STRAHLENDORF
Author Information
1. Department of Nursing, College of Medicine, Inha university, Incheon 402-751, South Korea.
- Publication Type:Original Article
- Keywords:
Purkinje cell (PC);
Oscillatory firing;
Nickel-sensitive inward current;
Apamin-sensitive outward current;
Zero slope resistance (ZSR) region
- MeSH:
Animals;
Apamin*;
Fires;
Nickel*;
Purkinje Cells*;
Rats
- From:The Korean Journal of Physiology and Pharmacology
1997;1(5):477-484
- CountryRepublic of Korea
- Language:English
-
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.
