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

Wu, Chun‐Fang; Haugland, Frank N.

doi:10.1523/jneurosci.05-10-02626.1985

Cited by 180 publications

(188 citation statements)

References 25 publications

Supporting

Mentioning

168

Contrasting

Order By: Relevance

“…Different components of membrane currents can be isolated via physiological and pharmacological manipulations. Since Drosophila larval muscle fibers do not have Na ϩ channels, the outward and inward currents are carried by K ϩ and Ca 2ϩ , respectively (52). K ϩ currents are recorded in Ca 2ϩ -free saline whereas voltage-gated Ca 2ϩ currents are recorded in the presence of a high concentration of Ba 2ϩ .…”

Section: Resultsmentioning

confidence: 99%

Differential behavioral state-dependence in the burst properties of CA3 and CA1 neurons

et al. 2006

View full text Add to dashboard Cite

It has been shown that presenilin is involved in maintaining Ca 2؉ homeostasis in neurons, including regulating endoplasmic reticulum (ER) Ca 2؉ storage. From studies of primary cultures and cell lines, however, its role in stress-induced responses is still controversial. In the present study we analyzed the effects of presenilin mutations on membrane currents and synaptic functions in response to stress using an in vivo preparation. We examined voltage-gated K ؉ and Ca 2؉ currents at the Drosophila larval neuromuscular junction (NMJ) with voltage-clamp recordings. Our data showed that both currents were generally unaffected by loss-of-function or Alzheimer's disease (AD) -associated presenilin mutations under normal or stress conditions induced by heat shock (HS) or ER stress. In larvae expressing the mutant presenilins, prolonged Ca 2؉ tail current, reflecting slower deactivation kinetics of Ca 2؉ channels, was observed 1 day after stress treatments were terminated. It was further demonstrated that the L-type Ca 2؉ channel was specifically affected under these conditions. Moreover, synaptic plasticity at the NMJ was reduced in larvae expressing the mutant presenilins. At the behavioral level, memory in adult flies was impaired in the presenilin mutants 1 day after HS. The results show that presenilin function is important during the poststress period and its impairment contributes to memory dysfunction observed during adaptation to normal conditions after stress. Our findings suggest a new stress-related mechanism by which presenilin may be implicated in the neuropathology of

show abstract

Section: Resultsmentioning

confidence: 99%

Differential behavioral state-dependence in the burst properties of CA3 and CA1 neurons

et al. 2006

View full text Add to dashboard Cite

show abstract

“…The cuticle was cut along the dorsal midline and pinned back. All internal organs were removed (28). Recordings were made from muscle fiber 12 (32) and were completed within 30 min from the start of dissection (16,29).…”

Section: Drosophila Strains and Genetics-the Amnmentioning

confidence: 99%

“…Voltage electrode was filled with 2.5 M KCl and the current electrode with a 3:1 mixture of 2.5 M KCl:2 M potassium citrate (28,30). Resistance of electrodes was in the range of 10 -20 Mohms.…”

Section: Drosophila Strains and Genetics-the Amnmentioning

confidence: 99%

Modulation of L-type Calcium Channels in Drosophila via a Pituitary Adenylyl Cyclase-activating Polypeptide (PACAP)-mediated Pathway

Bhattacharya

Lakhman

Singh

2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

Modulation of calcium channels plays an important role in many cellular processes. Previous studies have shown that the L-type Ca 2؉ channels in Drosophila larval muscles are modulated via a cAMP-protein kinase A (PKA)-mediated pathway. This raises questions on the identity of the steps prior to cAMP, particularly the endogenous signal that may initiate this modulatory cascade. We now present data suggesting the possible role of a neuropeptide, pituitary adenylyl cyclase-activating polypeptide (PACAP), in this modulation. Mutations in the amnesiac (amn) gene, which encodes a polypeptide homologous to human PACAP-38, reduced the L-type current in larval muscles. Conditional expression of a wild-type copy of the amn gene rescued the current from this reduction. Bath application of human PACAP-38 also rescued the current. PACAP-38 did not rescue the mutant current in the presence of PACAP-6 -38, an antagonist at type-I PACAP receptor. 2 ,5 -dideoxyadenosine, an inhibitor of adenylyl cyclase, prevented PACAP-38 from rescuing the amn current. In addition, 2 ,5 -dideoxyadenosine reduced the wild-type current to the level seen in amn, whereas it failed to further reduce the current observed in amn muscles. H-89, an inhibitor of PKA, suppressed the effect of PACAP-38 on the current. The above data suggest that PACAP, the type-I PACAP receptors, and adenylyl cyclase play a role in the modulation of L-type Ca 2؉ channels via cAMP-PKA pathway. The data also provide support for functional homology between human PACAP-38 and the amn gene product in Drosophila.

show abstract

“…Sh mutants have well characterized hyperactive behavioral and electrophysiological phenotypes (20,(22)(23)(24), making Sh a good candidate for dominant-negative suppression. Hyperexcitable Sh mutants, when combined with other K ϩ channel mutants such as ether-a-go-go, also have enlarged larval NMJs (7-9).…”

mentioning

confidence: 99%

Dissection of synaptic excitability phenotypes by using a dominant-negative Shaker K ⁺ channel subunit

Mosca

Carrillo

White

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

During nervous system development, synapses undergo morphological change as a function of electrical activity. In Drosophila, enhanced activity results in the expansion of larval neuromuscular junctions. We have examined whether these structural changes involve the pre-or postsynaptic partner by selectively enhancing electrical excitability with a Shaker dominant-negative (SDN) potassium channel subunit. We find that the SDN enhances neurotransmitter release when expressed in motoneurons, postsynaptic potential broadening when expressed in muscles and neurons, and selectively suppresses fast-inactivating, Shaker-mediated I A currents in muscles. SDN expression also phenocopies the canonical behavioral phenotypes of the Sh mutation. At the neuromuscular junction, we find that activity-dependent changes in arbor size occur only when SDN is expressed presynaptically. This finding indicates that elevated postsynaptic membrane excitability is by itself insufficient to enhance presynaptic arbor growth. Such changes must minimally involve increased neuronal excitability.activity ͉ behavioral genetics ͉ Drosophila E lectrical activity plays a prominent role in the development and plasticity of synapses (1-3). The glutamatergic neuromuscular junction (NMJ) of Drosophila is favorable for examining synaptogenesis and the role of electrical activity in synaptic growth and refinement (4, 5). In Drosophila, activity influences synaptic connectivity (6), size (7-9), and homeostasis (10, 11). Activity may also regulate retrograde signals that influence NMJ development (12)(13)(14). However, determining the relative contributions of pre-and postsynaptic excitability to synaptic development remains a significant challenge.Addressing this problem requires molecular tools that selectively alter excitability on either side of the synapse. Early success in suppressing excitability has involved the targeted expression of modified ion channels or receptors (10,15,16). A promising approach for enhancing electrical activity involves the dominantnegative suppression of K ϩ currents involved in membrane repolarization and excitability (17, 18).The Shaker (Sh) type I A K ϩ current of Drosophila plays a key role in regulating membrane excitability of neurons and muscles (19,20) and also influences the processing of graded potentials (21). Sh mutants have well characterized hyperactive behavioral and electrophysiological phenotypes (20,(22)(23)(24), making Sh a good candidate for dominant-negative suppression. Hyperexcitable Sh mutants, when combined with other K ϩ channel mutants such as ether-a-go-go, also have enlarged larval NMJs (7-9). However, whether these structural changes arise from pre-or postsynaptic membrane hyperexcitability has remained unresolved, because the Sh mutation affects both neurons and muscle.To dissect these changes, we have developed a Sh dominantnegative (SDN) transgene as a tool for targeted enhancement of electrical excitability. SDN effectively suppresses I A, as demonstrated by voltage-clamp analysis of muscle...

show abstract

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

Cited by 180 publications

References 25 publications

Differential behavioral state-dependence in the burst properties of CA3 and CA1 neurons

Differential behavioral state-dependence in the burst properties of CA3 and CA1 neurons

Modulation of L-type Calcium Channels in Drosophila via a Pituitary Adenylyl Cyclase-activating Polypeptide (PACAP)-mediated Pathway

Dissection of synaptic excitability phenotypes by using a dominant-negative Shaker K ⁺ channel subunit

Contact Info

Product

Resources

About

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

Cited by 180 publications

References 25 publications

Differential behavioral state-dependence in the burst properties of CA3 and CA1 neurons

Differential behavioral state-dependence in the burst properties of CA3 and CA1 neurons

Modulation of L-type Calcium Channels in Drosophila via a Pituitary Adenylyl Cyclase-activating Polypeptide (PACAP)-mediated Pathway

Dissection of synaptic excitability phenotypes by using a dominant-negative Shaker K + channel subunit

Contact Info

Product

Resources

About

Dissection of synaptic excitability phenotypes by using a dominant-negative Shaker K ⁺ channel subunit