Charybdotoxin and apamin sensitivity of the calcium-dependent repolarization and the afterhyperpolarization in neostriatal neurons - PubMed (original) (raw)

Charybdotoxin and apamin sensitivity of the calcium-dependent repolarization and the afterhyperpolarization in neostriatal neurons

J C Pineda et al. J Neurophysiol. 1992 Jul.

Abstract

1. Intracellular recordings from neostriatal neurons in an in vitro slice preparation of the rat brain were used to analyze the pharmacological sensitivity of the action potential (AP) repolarization and the afterhyperpolarization (AHP) that follows a single action potential. The interspike voltage trajectory and the AHP could be divided into two main parts: a fast component lasting a few milliseconds and better observed during a train of spikes, and a slow component lasting approximately 250 ms and that comprises the main portion of the AHP. In some cells, a slow (up to 1 s) component of low amplitude was also detected. 2. Single APs were elicited at two imposed membrane potentials (around -60 and around -80 mV). The AP amplitude was larger, the repolarization rate was faster, and the duration was shorter when spikes were evoked at -80 mV. When measured from the -60 mV holding potential, the afterpotential was an AHP with peak amplitude of -5 mV. The afterpotential became a delayed depolarization (DD) at -80 mV. 3. Firing frequency adaptation was voltage sensitive. The firing of APs induced by long intracellular current pulses from a holding potential of -80 mV exhibited only a slow-frequency adaptation (time constant of seconds). However, at -60 mV, an initial and faster frequency adaptation was evident (time constant of tens of milliseconds). 4. The Ca2+ channel blocker Cd2+ retarded AP repolarization rate. This effect correlated with a significant block of the fast and slow components of the AHP. In contrast, Ni2+ had no significant effects on the same parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

PubMed Disclaimer

Cited by

Duration differences of corticostriatal responses in striatal projection neurons depend on calcium activated potassium currents.
Arias-García MA, Tapia D, Flores-Barrera E, Pérez-Ortega JE, Bargas J, Galarraga E. Arias-García MA, et al. Front Syst Neurosci. 2013 Oct 4;7:63. doi: 10.3389/fnsys.2013.00063. eCollection 2013. Front Syst Neurosci. 2013. PMID: 24109439 Free PMC article.
P2Y1 receptor modulation of Ca2+-activated K+ currents in medium-sized neurons from neonatal rat striatal slices.
Coppi E, Pedata F, Gibb AJ. Coppi E, et al. J Neurophysiol. 2012 Feb;107(3):1009-21. doi: 10.1152/jn.00816.2009. Epub 2011 Nov 30. J Neurophysiol. 2012. PMID: 22131374 Free PMC article.
Kv7/KCNQ/M and HCN/h, but not KCa2/SK channels, contribute to the somatic medium after-hyperpolarization and excitability control in CA1 hippocampal pyramidal cells.
Gu N, Vervaeke K, Hu H, Storm JF. Gu N, et al. J Physiol. 2005 Aug 1;566(Pt 3):689-715. doi: 10.1113/jphysiol.2005.086835. Epub 2005 May 12. J Physiol. 2005. PMID: 15890705 Free PMC article.
Comparison of Hermissenda type a and type B photoreceptors: response to light as a function of intensity and duration.
Mo JL, Blackwell KT. Mo JL, et al. J Neurosci. 2003 Sep 3;23(22):8020-8. doi: 10.1523/JNEUROSCI.23-22-08020.2003. J Neurosci. 2003. PMID: 12954863 Free PMC article.
Differential roles of apamin- and charybdotoxin-sensitive K+ conductances in the generation of inferior olive rhythmicity in vivo.
Lang EJ, Sugihara I, Llinás R. Lang EJ, et al. J Neurosci. 1997 Apr 15;17(8):2825-38. doi: 10.1523/JNEUROSCI.17-08-02825.1997. J Neurosci. 1997. PMID: 9092604 Free PMC article.

Charybdotoxin and apamin sensitivity of the calcium-dependent repolarization and the afterhyperpolarization in neostriatal neurons - PubMed (original) (raw)