Viral vector-mediated expression of K+ channels regulates electrical excitability in skeletal muscle

Falk, Torsten; Kilani, RK; Yool, AJ; Sherman, SJ

doi:10.1038/sj.gt.3301539

Cited by 13 publications

(9 citation statements)

References 22 publications

(25 reference statements)

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“…Channel‐based silencing strategies could mimic either the endogenous inhibition arising from activation of K + channels (for instance, GABA B receptors coupled to GIRK channels) or that arising from activation of Cl − channels (for instance, GABA A receptors). Most strategies employ K + channels [1–8]. K + channels have the advantage that they can be chosen, or modified, to display various voltage‐dependent and rectifying characteristics.…”

Section: Resultsmentioning

confidence: 99%

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Selective elimination of glutamate activation and introduction of fluorescent proteins into a Caenorhabditis elegans chloride channel

Slimko

Lester

2002

FEBS Letters

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Glutamate-gated chloride (GluCl) channels from invertebrates can be activated by ivermectin (IVM) to produce electrical silencing in mammalian neurons. To improve this GluCl/IVM strategy, we sought to mutate the Caenorhabditis elegans GluCl channels so that they become insensitive to glutamate but retain their sensitivity to IVM. Based on structuref unction studies of nicotinic acetylcholine receptor superfamily members, we tested in oocytes 19 point mutants at 16 residues in the L L-subunit likely to be involved in the response to glutamate. Y182F reduces the glutamate response by greater than six-fold, with little change to IVM responses, when coexpressed with wild-type (WT) GluCl K K. For GluCl KL KL(Y182F), the EC 50 and Hill coe⁄cient for glutamate are similar to those of WT, indicating that the mutant decreases the e⁄cacy of glutamate, but not the potency. Also, £uorescent proteins (enhanced green £uorescent protein, enhanced yellow £uorescent protein, enhanced cyan £uorescent protein; XFP) were inserted into the M3^M4 loop of the GluCl K K, L L and L L(Y182F). We found no signi¢cant functional di¡erence between these XFP-tagged receptors and WT receptors. The modi¢ed GluCl channel, without glutamate sensitivity but with a £uorescent tag, may be more useful in GluCl silencing strategies. ß

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Section: Resultsmentioning

confidence: 99%

“…Several recent studies describe expression of exogenous ion channels in order to change the electrical properties of neurons [1–8]. Our laboratory has developed a procedure that employs the glutamate‐gated chloride (GluCl) channels from Caenorhabditis elegans [9–11].…”

Section: Introductionmentioning

confidence: 99%

Selective elimination of glutamate activation and introduction of fluorescent proteins into a Caenorhabditis elegans chloride channel

Slimko

Lester

2002

FEBS Letters

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“…Consistent with findings in adult tissue (Chung et al, 2000), members of the Kv1 class of voltage gated K + were present in cultured striatal neurons. The genetic manipulation of voltage-gated K + channels as a means of altering electrical has been explored by our laboratory (Falk et al, 2001;2003) and others (White et al, 2001). This technique will be particularly important to the development of therapeutic strategies designed to modify brain circuits with abnormal activity due to neurological disease.…”

Section: Discussionmentioning

confidence: 99%

Neurochemical and electrophysiological characteristics of rat striatal neurons in primary culture

Falk

Zhang

Erbe

et al. 2005

J of Comparative Neurology

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Neurons maintained in dispersed primary culture offer a number of advantages as a model system and are particularly well-suited for studies of the intrinsic electrical properties of neurons by patch-clamp. We have characterized the immunocytochemical and electrophysiological properties of cultured rat striatal neurons as they develop in vitro in order to compare this model system to the known properties found in vivo. We found a high abundance of cells in vitro corresponding to the principal striatal output neuron, the medium spiny neuron.Immunocytochemical studies indicate that these cells have both dopamine-1 and dopamine-2 receptors and that there is overlap in their expression within the population of neurons. Semiquantitative analysis revealed bimodal distributions of dopamine receptor expression among the population of neurons. The principal peptide neurotransmitters substance P and enkephalin were present but at reduced levels compared to adult preparations. Other striatal markers such as calbindin, calretinin and the cannabinoid-1 receptor were abundant. An immunocytochemical survey of voltage-gated K + channel subunits characteristic of adult tissue demonstrated the presence in vitro of Kv1.1, Kv1.4, Kv4.2, Kv4.3 and Kvβ1.1 which have been associated with the rapidly inactivating currents. Electrophysiological studies employing voltage clamp revealed that outward currents had a large inactivating (A-type) component characteristic of mature basal ganglia. Current clamp studies reveal complex spontaneous firing patterns in a subset of neurons including bursting behaviors superimposed on a slow depolarization. The inward rectifying channels Kir2.1 and Kir2.3 which are specific to particular compartments in adult striatum were present in culture. KeywordsStriatal neurons; Dopamine receptors; Potassium channels; substance P; Enkephalin; Calcium binding proteins Neurons derived from fetal rodent brain and maintained in primary culture have been widely employed as model systems to study developmental processes and physiology at the singlecell level (Mandel and Banker, 1996). Significant progress has been made in the study of neuronal polarity (Dotti and Banker, 1991), G protein-coupled receptors (Vilchis et al., 2002;Morris et al., 2000), ion channel physiology (Sucher et al., 2000;Parak et al., 2001;Centonze et al., 2002) and inhibitory synaptic transmission (Kowalski et al., 1995) by using primary neuronal culture. Striatal neurons maintained in primary culture have been employed to study physiology of the NMDA receptors (Popp et al., 1998), opioid receptors (Vaysse et al., 1990), metabotropic glutamate receptors (Paolillo et al., 1998), and acetylcholine receptors (Tence et al., 1995 These preparations are particularly well suited for gene-transfer studies intended to manipulate electrical activity, since transduced neurons can be identified in the living state by the use of fluorescent reporter genes and their electrophysiological properties may be studied individually by patch clamp methods (Falk...

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“…This will allow for the nondestructive testing of engineered muscle in culture, as a quantitative biomarker of muscle contractility and the process of muscle tissue development in vitro. Muscle excitability is known to be related to the Naþ-Kþ membrane pump, 28,29,45 so measures of excitability allow a nondestructive probe of the development of this important cellular system. For example, from Figure 3, the development of the neonatal rat muscle, especially prior to 44 days postpartum, could be readily tracked using the chronaxie as a biomarker.…”

Section: Dennis and Dowmentioning

confidence: 99%

“…Even the potential for the use of electrical stimulation to attenuate or reverse the effects of denervation on muscle was first proposed by Reid as early as 1841. 11 More recent work in the area of muscle excitability generally relates to technological developments in the fields of functional or therapeutic electrical stimulation, 18-23 tissue engineering, 1,2,24,25 and biomechatronics, in which functional excitable tissue is incorporated into synthetic devices such as biohybrid robotics and prosthetics, 26,27 with only occasional measures related purely to the scientific study of the basic biology of normal muscle development, 28,29 disease, 30,31 or denervation. 18,32 In the classical work on nerve and muscle excitability, ''rheobase'' and ''chronaxie'' were the terms employed to describe the threshold stimulus for depolarization of portions of membranes from individual excitable cells.…”

Section: Introductionmentioning

confidence: 99%

Excitability of Skeletal Muscle during Development, Denervation, and Tissue Culture

Dennis

Dow

2007

Tissue Engineering

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A quantitative understanding of the bulk excitability of skeletal muscle tissues is important for the design of muscle tissue bioreactor systems, implantable muscle stimulators, and other systems where electrical pulses are employed to elicit contractions in muscle tissue both in vitro and in vivo. The purpose of the present study is to systematically compare the excitability of mammalian (rat) skeletal muscle under a range of conditions (including neonatal development, denervation, and chronic in vivo stimulation of denervated muscle) and of self-organized muscle tissue constructs engineered in vitro from both primary cells and cell lines. Excitability is represented by rheobase (R(50), units = V/mm) and chronaxie (C(50), units = microseconds) values, with lower values for each indicating greater excitability. Adult skeletal muscle is the most excitable (R(50) ~ 0.29, C(50) ~ 100); chronically denervated whole muscles (R(50) ~ 2.54, C(50) ~ 690) and muscle engineered in vitro from cell lines (C2C12 + 10T1/2) (R(50) ~ 1.93, C(50) ~ 416) have exceptionally low excitability; muscle engineered in vitro from primary myocytes (R(50) ~ 0.99, C(50) ~ 496) has excitability similar to that of day 14 neonatal rat muscle (R(50) ~ 0.65, C(50) ~ 435); stimulated-denervated muscles retain excellent excitability when chronically electrically stimulated (R(50) ~ 0.40, C(50) ~ 100); and neonatal rat muscle excitability improves during the first 6 weeks of development, steadily approaching that of adult muscle.

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Viral vector-mediated expression of K+ channels regulates electrical excitability in skeletal muscle

Abstract: Modification of K

Cited by 13 publications

References 22 publications

Selective elimination of glutamate activation and introduction of fluorescent proteins into a Caenorhabditis elegans chloride channel

Selective elimination of glutamate activation and introduction of fluorescent proteins into a Caenorhabditis elegans chloride channel

Neurochemical and electrophysiological characteristics of rat striatal neurons in primary culture

Excitability of Skeletal Muscle during Development, Denervation, and Tissue Culture

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