Cellular localization of Shab and Shaw potassium channels in the lobster stomatogastric ganglion

French, L.B; Lanning, Cathy Cole; Matly, M; Harris-Warrick, Ronald M.

doi:10.1016/j.neuroscience.2003.08.036

Cited by 15 publications

(10 citation statements)

References 26 publications

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“…6(B,G,L)]. A similar neuropil localization was reported (French et al, 2004) for Shaw in the lobster stomatogastric ganglion using an antibody developed against a lobster Shaw C-terminus peptide (identical to amino acids 413-429 of Drosophila Shaw). Images in this figure were acquired at the same confocal settings and tissues processed in parallel to allow semiquantitative comparison of subcellular localization of transgenic and endogenous Shaw.…”

Section: Shaw Full-length and Truncated Transgene Products Are Differsupporting

confidence: 55%

Shaw potassium channel genes inDrosophila

Hodge¹,

Choi

O’Kane

et al. 2005

J. Neurobiol.

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Drosophila Shaw encodes a voltage-insensitive, slowly activating, noninactivating K(+) current. The functional and developmental roles of this channel are unknown. In this study, we use a dominant transgenic strategy to investigate Shaw function and describe a second member of the Shaw family, Shawl. In situ hybridization showed that the two Shaw family genes, Shaw and Shawl, have largely nonoverlapping expression patterns in embryos. Shaw is expressed mainly in excitable cells of the CNS and PNS of late embryos. Shawl is expressed in many nonexcitable cell types: ubiquitously in embryos until the germband extends, then transiently in the developing CNS and PNS, becoming restricted to progressively smaller subsets of the CNS. Ectopic full-length and truncated Shaw localize differently within neurons, and produce uneclosed small pupae and adults with unfurled wings and softened cuticle. This phenotype was mapped to the crustacean cardioactive peptide (CCAP)-neuropeptide circuit. Widespread expression of Shaw in the nervous system results in a reduction in body mass, ether-induced shaking, and lethality. Expression of full-length Shaw had more extreme phenotypic consequences and caused earlier lethality than expression of truncated Shaw in a given GAL4 pattern. Whole cell recordings from ventral ganglion motor neurons expressing the truncated Shaw protein suggest that a major role of Shaw channels in these cells is to contribute to the resting potential.

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Section: Shaw Full-length and Truncated Transgene Products Are Differsupporting

confidence: 55%

Shaw potassium channel genes inDrosophila

Hodge¹,

Choi

O’Kane

et al. 2005

J. Neurobiol.

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“…The synaptic currents were present at uniform density only in the neurite compartments, and the axonal currents (I leak,ax , I Na , I Kda , and I Aa ) were present only in the axon compartment. All of these distributions are simplified versions of the true channel distributions in biological LP neurons (Hartline and Graubard, 1992; Baro and Harris-Warrick, 1998; Baro et al, 2000; French et al, 2004), but they are likely to be reasonable approximations at the level of detail we are interested in at present. The maximal conductances of most voltage-gated conductances were set to values close to those seen in the voltage-clamp recordings.…”

Section: Methodsmentioning

confidence: 99%

How Multiple Conductances Determine Electrophysiological Properties in a Multicompartment Model

Taylor¹,

Goaillard²,

Marder³

2009

J. Neurosci.

185

280

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Most neurons have large numbers of voltage-and time-dependent currents that contribute to their electrical firing patterns. Because these currents are nonlinear, it can be difficult to determine the role each current plays in determining how a neuron fires. The lateral pyloric (LP) neuron of the stomatogastric ganglion of decapod crustaceans has been studied extensively biophysically. We constructed ϳ600,000 versions of a four-compartment model of the LP neuron and distributed 11 different currents into the compartments. From these, we selected ϳ1300 models that match well the electrophysiological properties of the biological neuron. Interestingly, correlations that were seen in the expression of channel mRNA in biological studies were not found across the ϳ1300 admissible LP neuron models, suggesting that the electrical phenotype does not require these correlations. We used cubic fits of the function from maximal conductances to a series of electrophysiological properties to ask which conductances predominantly influence input conductance, resting membrane potential, resting spike rate, phasing of activity in response to rhythmic inhibition, and several other properties. In all cases, multiple conductances contribute to the measured property, and the combinations of currents that strongly influence each property differ. These methods can be used to understand how multiple currents in any candidate neuron interact to determine the cell's electrophysiological behavior.

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“…In a stomatogastric neuron, antibody staining against Shal and Shaker channels revealed that Shal is targeted to proximal compartments and axon terminals, while Shaker was exclusively found along the path of the axon in the motor nerve (Baro et al , 2000). The same axons also express both Shab and Shaw channels (French et al , 2004). A similar preferred distribution of Shaker over Shal in axons may be present in many insect neurons (Wicher et al , 2001).…”

Section: Diversity Of Axonsmentioning

confidence: 99%

Beyond faithful conduction: Short-term dynamics, neuromodulation, and long-term regulation of spike propagation in the axon

Bucher¹,

Goaillard²

2011

Progress in Neurobiology

171

190

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Most spiking neurons are divided into functional compartments: a dendritic input region, a soma, a site of action potential initiation, an axon trunk and its collaterals for propagation of action potentials, and distal arborizations and terminals carrying the output synapses. The axon trunk and lower order branches are probably the most neglected and are often assumed to do nothing more than faithfully conducting action potentials. Nevertheless, there are numerous reports of complex membrane properties in non-synaptic axonal regions, owing to the presence of a multitude of different ion channels. Many different types of sodium and potassium channels have been described in axons, as well as calcium transients and hyperpolarization-activated inward currents. The complex time- and voltage-dependence resulting from the properties of ion channels can lead to activity-dependent changes in spike shape and resting potential, affecting the temporal fidelity of spike conduction. Neural coding can be altered by activity-dependent changes in conduction velocity, spike failures, and ectopic spike initiation. This is true under normal physiological conditions, and relevant for a number of neuropathies that lead to abnormal excitability. In addition, a growing number of studies show that the axon trunk can express receptors to glutamate, GABA, acetylcholine or biogenic amines, changing the relative contribution of some channels to axonal excitability and therefore rendering the contribution of this compartment to neural coding conditional on the presence of neuromodulators. Long-term regulatory processes, both during development and in the context of activity-dependent plasticity may also affect axonal properties to an underappreciated extent.

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Cellular localization of Shab and Shaw potassium channels in the lobster stomatogastric ganglion

Cited by 15 publications

References 26 publications

Shaw potassium channel genes inDrosophila

Shaw potassium channel genes inDrosophila

How Multiple Conductances Determine Electrophysiological Properties in a Multicompartment Model

Beyond faithful conduction: Short-term dynamics, neuromodulation, and long-term regulation of spike propagation in the axon

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