Abnormal action potentials associated with the
            <i>Shaker</i>
            complex locus of
            <i>Drosophila</i>

Tanouye, Mark A.; Ferrús, Alberto; Fujita, Shinobu C.

doi:10.1073/pnas.78.10.6548

Cited by 153 publications

(82 citation statements)

References 17 publications

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“…This is consistent with the electrophysiological phenotype of Sh mutants that produces modifications in neurotransmitter release (Jan et al, 1977) and action potentials (Tanouye et al, 1981). The most intense expression of Sh Kch found in defined regions of the adult head such as MB and OL neuropile agrees with that found in an earlier immunohistological study (Schwarz et al, 1990).…”

Section: Diverse Functional Roles Can Be Inferred From the Distributisupporting

confidence: 89%

Diverse Expression and Distribution ofShakerPotassium Channels during the Development of theDrosophilaNervous System

1997

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The spatio-temporal expression ofShaker(Sh) potassium channels (Kch) in the developing and adult nervous system ofDrosophilahas been studied at the molecular and histological level using specific antisera.ShKch are distributed in most regions of the nervous system, but their expression is restricted to only certain populations of cells.ShKch have been found in the following three locations: in synaptic areas of neuropile, in axonal fiber tracks, and in a small number of neuronal cell bodies. This wide subcellular localization, together with a diverse distribution, implicatesShKch in multiple neuronal functions.Experiments performed withShmutants that specifically eliminate a few of theShKch splice variants clearly demonstrate an abundant differential expression and usage of the wide repertoire ofShisoforms, but they do not support the idea of extensive segregation of these isoforms among different populations of neurons.ShKch are predominantly expressed at late stages of postembryonic development and adulthood. Strikingly, wide changes in the repertoire ofShsplice isoforms occur some time after the architecture of the nervous system is complete, indicating that the expression ofShKch contributes to the final refinements of neuronal differentiation. These late changes in the expression and distribution ofShKch seem to correlate with activity patterns suggesting thatShKch may be involved in adaptative mechanisms of excitability.

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Section: Diverse Functional Roles Can Be Inferred From the Distributisupporting

confidence: 89%

Diverse Expression and Distribution ofShakerPotassium Channels during the Development of theDrosophilaNervous System

1997

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“…At the larval neuromuscular junction, the Sh mutations have been associated with antidromic repetitive firing of motor axons resulting in prolonged transmitter release (Jan et al, 1977;Wu, 1982b, 1983). Intracellular recordings from adult giant axons revealed abnormal action potentials with delayed repolarization (Tanouye et al, 1981). Recent voltage clamp studies of adult (Salkoff and Wyman, 1981;Salkoff, 1983b) and larval muscles (Wu et al, 1983a;Wu and Ganetzky, 1984) confirm the previous suggestion that Sh mutations affect potassium currents (Jan et al, 1977).…”

supporting

confidence: 60%

“…The defects caused by Sh5 have been found to be consistently less extreme than those in ShKS'33 In all tissues examined (larval neuromuscular junctions: Jan et al, 1977; C. -F. Wu and B. Ganetzky, unpublished observations; adult "giant axons": Tanouye et al, 1981;adult muscles: Salkoff and Wyman, 1981; larval muscles: this report). However, voltage clamp studies of the residual IA in Sh5 revealed important differences in the manner in which adult and larval muscles are affected.…”

Section: The Journal Of Neuroscience Potassium Currents In Drosophilamentioning

confidence: 68%

“…In terms of severity, consistency is found in the defects of ShKS'33, Sh", and Sh"', each causing delayed repolarization of action potentials in adult "giant axons" (Tanouye et al, 1981), prolonged transmission in larval neuromuscular junctions (Jan et al, 1977;Ganetzky and Wu, 1983;B. Ganetzky and C. -F. Wu, unpublished data), and complete elimination of In in both pupal (Salkoff, 1983b; ShM not tested) and larval muscles.…”

Section: The Journal Of Neuroscience Potassium Currents In Drosophilamentioning

confidence: 92%

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Voltage clamp analysis of membrane currents in larval muscle fibers of Drosophila: alteration of potassium currents in Shaker mutants

Wu¹,

Haugland²

1985

J. Neurosci.

180

168

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The body wall muscles in Drosophila larvae are suitable for voltage clamp analysis of changes in membrane excitability caused by mutations.Both inward and outward ionic currents are present in these muscle fibers. The inward current is mediated by voltage-dependent Ca*+ channels. In Ca2+-free saline, the inward current is eliminated.The remaining outward K+ currents consist of two distinct components, an early transient IA and a delayed steady IK, which are separable by differences in the rate and voltage dependence of activation and inactivation. The steady-state and kinetic properties of the activation and inactivation processes of these two currents are analyzed.

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“…Little is known, however, about how the electrical activities of central neurons are affected. Intracellular recording of action potentials has been performed on certain Drosophila neurons in vivo (Ikeda and Kaplan, 1974;Tanouye et al, 1981), but additional electrophysiological analyses have been limited by technical difficulties. The Drosophila "giant" neuron culture system has provided a preparation accessible to electrophysiological characterizations of neuronal activity and the underlying ionic currents Wu, 1991, 1993;Zhao and Wu, 1994).…”

mentioning

confidence: 99%

Alterations in Frequency Coding and Activity Dependence of Excitability in Cultured Neurons ofDrosophilaMemory Mutants

Zhao

1997

J. Neurosci.

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Mutants of the Drosophila dunce (dnc) and rutabaga (rut) genes, which encode a cAMP-specific phosphodiesterase and a calcium/calmodulin-responsive adenylyl cyclase, respectively, are deficient in short-term memory. Altered synaptic plasticity has been demonstrated at neuromuscular junctions in these mutants, but little is known about how their central neurons are affected. We examined this problem by using the "giant" neuron culture, which offers a unique opportunity to analyze mutational effects on neuronal activity and the underlying ionic currents in Drosophila. On the basis of instantaneous frequency and first latency of spikes evoked by current steps, four categories of firing patterns (tonic, adaptive, delayed, and interrupted) were identified in wild-type neurons, revealing interesting parallels to those commonly observed in vertebrate CNS neurons. The distinct firing patterns were correlated with expression of different ratios of 4-aminopyridine-and tetraethylammoniumsensitive K ϩ currents. Subsets of dnc and rut neurons displayed abnormal spontaneous spikes and altered firing patterns. Altered frequency coding in mutant neurons was demonstrated further by using stimulation protocols involving conditioning with previous activity. Abnormal spike activity and reduced K ϩ current remained in double-mutant neurons, suggesting that the opposite effects on cAMP metabolism by dnc and rut do not counterbalance the mutual functional defects. The aberrant spontaneous activity and altered frequency coding in different stimulus paradigms may present problems in the stability and reliability of neural circuits for information processing during certain behavioral tasks, raising the possibility of modulation in neuronal excitability as a cellular mechanism underlying learning and memory.

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Abnormal action potentials associated with the Shaker complex locus of Drosophila

Cited by 153 publications

References 17 publications

Diverse Expression and Distribution ofShakerPotassium Channels during the Development of theDrosophilaNervous System

Diverse Expression and Distribution ofShakerPotassium Channels during the Development of theDrosophilaNervous System

Voltage clamp analysis of membrane currents in larval muscle fibers of Drosophila: alteration of potassium currents in Shaker mutants

Alterations in Frequency Coding and Activity Dependence of Excitability in Cultured Neurons ofDrosophilaMemory Mutants

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