Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
The pharmacology and roles of two K+ channels in motor pattern generation in the Xenopus embryo.
Kuenzi FM, Dale N.
???displayArticle.abstract???
The spinal neurons of the Xenopus embryo that participate in the swimming motor pattern possess two kinetically distinct sets of potassium currents: the fast IKf and sodium-dependent IKNa, which together constitute approximately 80% of the outward current; and the slow IKs, which constitutes the remainder. To study their respective roles in cell excitability and the swimming pattern, we have characterized their pharmacological properties. Catechol selectively blocked the fast potassium currents (IC50, approximately 10 microM). The block was voltage-dependent, with partial unblocking occurring at positive voltages. alpha-Dendrotoxin and dendrotoxin-I selectively blocked the slow potassium current. Catechol and the dendrotoxins had different effects on membrane excitability: catechol caused spike broadening but had little effect on repetitive firing, whereas both dendrotoxins markedly increased repetitive firing without affecting spike width. By applying these agents to the whole embryo, we tested the role of the fast and slow currents in motor pattern generation. Catechol had little effect on fictive swimming, suggesting that the fast K+ currents are not critical to circuit operation. However, dendrotoxin disrupted swimming early in the episode and increased the duration of ventral root bursts. The slow K+ current, which is a minor component of the total outward current, thus appears to play an important role in motor pattern generation.
Arshavsky YuI,
Neuronal control of swimming locomotion: analysis of the pteropod mollusc Clione and embryos of the amphibian Xenopus.
1993, Pubmed,
Xenbase
Arshavsky YuI,
Neuronal control of swimming locomotion: analysis of the pteropod mollusc Clione and embryos of the amphibian Xenopus.
1993,
Pubmed
,
Xenbase Brew,
Two voltage-dependent K+ conductances with complementary functions in postsynaptic integration at a central auditory synapse.
1995,
Pubmed Burger,
Xenopus spinal neurons express Kv2 potassium channel transcripts during embryonic development.
1996,
Pubmed
,
Xenbase Byrne,
Analysis of ionic conductance mechanisms in motor cells mediating inking behavior in Aplysia californica.
1980,
Pubmed Byrne,
Quantitative aspects of ionic conductance mechanisms contributing to firing pattern of motor cells mediating inking behavior in Aplysia californica.
1980,
Pubmed Connor,
Neural repetitive firing: a comparative study of membrane properties of crustacean walking leg axons.
1975,
Pubmed Dale,
Experimentally derived model for the locomotor pattern generator in the Xenopus embryo.
1995,
Pubmed
,
Xenbase Dale,
The Isolation and Identification of Spinal Neurons That Control Movement in the Xenopus Embryo.
1991,
Pubmed
,
Xenbase Dale,
Kinetic characterization of the voltage-gated currents possessed by Xenopus embryo spinal neurons.
1995,
Pubmed
,
Xenbase Dale,
Regulation of rhythmic movements by purinergic neurotransmitters in frog embryos.
1996,
Pubmed
,
Xenbase Dale,
A large, sustained Na(+)- and voltage-dependent K+ current in spinal neurons of the frog embryo.
1993,
Pubmed
,
Xenbase el Manira,
Calcium-dependent potassium channels play a critical role for burst termination in the locomotor network in lamprey.
1994,
Pubmed Erdélyi,
The A-type potassium current: catechol-induced blockage in snail neurons.
1988,
Pubmed Golowasch,
Ionic currents of the lateral pyloric neuron of the stomatogastric ganglion of the crab.
1992,
Pubmed Grudt,
kappa-Opioid receptors also increase potassium conductance.
1993,
Pubmed Halliwell,
Central action of dendrotoxin: selective reduction of a transient K conductance in hippocampus and binding to localized acceptors.
1986,
Pubmed Harris-Warrick,
Dopamine modulation of two subthreshold currents produces phase shifts in activity of an identified motoneuron.
1995,
Pubmed Harris-Warrick,
Dopamine modulation of transient potassium current evokes phase shifts in a central pattern generator network.
1995,
Pubmed Ito,
Catechol: a potent and specific inhibitor of the fast potassium channel in frog primary afferent neurones.
1986,
Pubmed Kahn,
The central nervous origin of the swimming motor pattern in embryos of Xenopus laevis.
1982,
Pubmed
,
Xenbase Kahn,
Experiments on the central pattern generator for swimming in amphibian embryos.
1982,
Pubmed
,
Xenbase Kehl,
Catechol blocks the fast outward potassium current in melanotrophs of the rat pituitary.
1991,
Pubmed McCormick,
A model of the electrophysiological properties of thalamocortical relay neurons.
1992,
Pubmed Nadim,
Modeling the leech heartbeat elemental oscillator. I. Interactions of intrinsic and synaptic currents.
1995,
Pubmed Nadim,
A slow outward current activated by FMRFamide in heart interneurons of the medicinal leech.
1997,
Pubmed Olsen,
Modeling the leech heartbeat elemental oscillator. II. Exploring the parameter space.
1995,
Pubmed Rehm,
Voltage-gated K+ channels of the mammalian brain.
1991,
Pubmed Ribera,
Primary sensory neurons express a Shaker-like potassium channel gene.
1993,
Pubmed
,
Xenbase Ribera,
Differentiation of IKA in amphibian spinal neurons.
1990,
Pubmed
,
Xenbase Roberts,
How does a nervous system produce behaviour? A case study in neurobiology.
1990,
Pubmed
,
Xenbase Roberts,
The neuroanatomy of an amphibian embryo spinal cord.
1982,
Pubmed
,
Xenbase Roberts,
Intracellular recordings from spinal neurons during 'swimming' in paralysed amphibian embryos.
1982,
Pubmed
,
Xenbase Roberts,
Characterization and Function of Spinal Excitatory Interneurons with Commissural Projections in Xenopus laevis embryos.
1990,
Pubmed
,
Xenbase Sah,
Potassium currents contributing to action potential repolarization and the afterhyperpolarization in rat vagal motoneurons.
1992,
Pubmed Schauf,
Dendrotoxin blocks potassium channels and slows sodium inactivation in Myxicola giant axons.
1987,
Pubmed Scott,
Antibodies specific for distinct Kv subunits unveil a heterooligomeric basis for subtypes of alpha-dendrotoxin-sensitive K+ channels in bovine brain.
1994,
Pubmed Sillar,
The development of swimming rhythmicity in post-embryonic Xenopus laevis.
1991,
Pubmed
,
Xenbase Simmons,
k-Opioid receptor activation of a dendrotoxin-sensitive potassium channel mediates presynaptic inhibition of mossy fiber neurotransmitter release.
1996,
Pubmed Soffe,
Two distinct rhythmic motor patterns are driven by common premotor and motor neurons in a simple vertebrate spinal cord.
1993,
Pubmed
,
Xenbase Soffe,
Active and Passive Membrane Properties of Spinal Cord Neurons that Are Rhythmically Active during Swimming in Xenopus Embryos.
1990,
Pubmed
,
Xenbase Soffe,
Motor patterns for two distinct rhythmic behaviors evoked by excitatory amino acid agonists in the Xenopus embryo spinal cord.
1996,
Pubmed
,
Xenbase Tegnér,
Low-voltage-activated calcium channels in the lamprey locomotor network: simulation and experiment.
1997,
Pubmed Wall,
A role for potassium currents in the generation of the swimming motor pattern of Xenopus embryos.
1994,
Pubmed
,
Xenbase Wall,
A slowly activating Ca(2+)-dependent K+ current that plays a role in termination of swimming in Xenopus embryos.
1995,
Pubmed
,
Xenbase Werkman,
Charybdotoxin, dendrotoxin and mast cell degranulating peptide block the voltage-activated K+ current of fibroblast cells stably transfected with NGK1 (Kv1.2) K+ channel complementary DNA.
1992,
Pubmed
