Channel-specific effects of n -alkyl sulphate anions on three Shaker -related potassium channels expressed in Xenopus oocytes

1997 ◽  
Vol 434 (1) ◽  
pp. 132-136
Author(s):  
A. A. Elliott ◽  
J. R. Elliott
Keyword(s):  
Potassium Channels ◽  
Xenopus Oocytes ◽  
Alkyl Sulphate ◽  
Specific Effects

Effects of antiarrhythmic drugs on cloned cardiac voltage-gated potassium channels expressed in Xenopus oocytes

2000 ◽  
Vol 362 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Sascha Rolf ◽  
Wilhelm Haverkamp ◽  
Martin Borggrefe ◽  
Ulrich Mußhoff ◽  
Lars Eckardt ◽  
...  
Keyword(s):  
Potassium Channels ◽  
Xenopus Oocytes ◽  
Antiarrhythmic Drugs ◽  
Voltage Gated

scholarly journals Translocation of RNA-coated gold particles through the nuclear pores of oocytes.

1988 ◽  
Vol 106 (3) ◽  
pp. 575-584 ◽  
Author(s):  
S I Dworetzky ◽  
C M Feldherr
Keyword(s):  
Electron Microscopy ◽  
Xenopus Oocytes ◽  
Particle Distribution ◽  
Polyglutamic Acid ◽  
5S Rna ◽  
Nuclear Pores ◽  
Gold Particles ◽  
Specific Effects ◽  
Tracer Particles ◽  
Nuclear Injection

In the present study, various sized gold particles coated with tRNA, 5S RNA, or poly(A) were used to localize and characterize the pathways for RNA translocation to the cytoplasm. RNA-coated gold particles were microinjected into the nucleus of Xenopus oocytes. The cells were fixed after 15, 60 min, or 6 h, and the particle distribution was later observed by electron microscopy. Similar results were obtained with all classes of RNA used. After nuclear injection, particles ranging from 20-230 A in diameter were observed within central channels of the nuclear pores and in the cytoplasm immediately adjacent to the pores. Particles of this size would not be expected to diffuse through the pores, suggesting that some form of mediated transport occurred. In addition, it was found that the translocation process is saturable. At least 97% of the pores analyzed appeared to be involved in the translocation process. Gold coated with nonphysiological polynucleotides (poly[I] or poly[dA]) were also translocated. When nuclei were injected with either BSA-, ovalbumin-, polyglutamic acid-, or PVP-coated gold, the particles were essentially excluded from the pores. These results indicate that the accumulation of RNA-gold within the pores and adjacent cytoplasm was not due to non-specific effects. We conclude that the translocation sites for gold particles coated with different classes of RNA are located in the centers of the nuclear pores and that particles at least 230 A in diameter can cross the envelope. Tracer particles injected into the cytoplasm were observed within the nuclear pores in areas near the site of injection. However, only a small percentage of the particles actually entered the nucleus. It was also determined, by performing double injection experiments, that individual pores are bifunctional, that is, capable of transporting both proteins and RNA.

Gating currents of inactivating and non-inactivating potassium channels expressed in Xenopus oocytes

1991 ◽  
Vol 418 (4) ◽  
pp. 423-429 ◽  
Author(s):  
Walter St�hmer ◽  
Franco Conti ◽  
Martin Stocker ◽  
Olaf Pongs ◽  
Stefan H. Heinemann
Keyword(s):  
Potassium Channels ◽  
Xenopus Oocytes ◽  
Gating Currents

scholarly journals Function of Shaker Potassium Channels Produced by Cell-Free Translation Upon Injection into Xenopus Oocytes

2013 ◽  
Vol 104 (2) ◽  
pp. 197a
Author(s):  
Brian W. Jarecki ◽  
Shin-ichi Makino ◽  
Emily T. Beebe ◽  
Brian G. Fox ◽  
Baron Chanda
Keyword(s):  
Potassium Channels ◽  
Xenopus Oocytes ◽  
Free Translation ◽  
Shaker Potassium Channels

scholarly journals Dihydropyridine Action on Voltage-dependent Potassium Channels Expressed in Xenopus Oocytes

1997 ◽  
Vol 109 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Vladimir Avdonin ◽  
Erwin F. Shibata ◽  
Toshinori Hoshi
Keyword(s):  
Ion Channels ◽  
Potassium Channels ◽  
Xenopus Oocytes ◽  
K Channels ◽  
Open Time ◽  
Voltage Dependent ◽  
Ca2 Channels

Dihydropyridines (DHPs) are well known for their effects on L-type voltage-dependent Ca2+ channels. However, these drugs also affect other voltage-dependent ion channels, including Shaker K+ channels. We examined the effects of DHPs on the Shaker K+ channels expressed in Xenopus oocytes. Intracellular applications of DHPs quickly and reversibly induced apparent inactivation in the Shaker K+ mutant channels with disrupted N- and C-type inactivation. We found that DHPs interact with the open state of the channel as evidenced by the decreased mean open time. The DHPs effects are voltage-dependent, becoming more effective with hyperpolarization. A model which involves binding of two DHP molecules to the channel is consistent with the results obtained in our experiments.

scholarly journals Function of Shaker potassium channels produced by cell-free translation upon injection into Xenopus oocytes

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Brian W. Jarecki ◽  
Shin-ichi Makino ◽  
Emily T. Beebe ◽  
Brian G. Fox ◽  
Baron Chanda
Keyword(s):  
Potassium Channels ◽  
Xenopus Oocytes ◽  
Free Translation ◽  
Shaker Potassium Channels
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