Wyniki wyszukiwania

1

Transmembrane segment M2 of glycine receptor as a model system for the pore-forming structure of ion channels

100%

Bednarczyk P., Szewczyk A., Dolowy K.

Acta Biochimica Polonica

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2002

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tom 49

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nr 4

The glycine receptor belongs to the ligand-gated ion channel superfamily. It is a chloride conducting channel composed of four transmembrane domains. It was previously shown that the second transmembrane domain (M2) of the glycine receptor forms an ion conduction pathway throught lipid bilayers. The amino-acid sequence of the transmembrane segment M2 of the glycine receptor has a high homology to all receptors of the ligand-gated ion channel superfamily. In our report, we have used a synthetic M2 peptide. It was incorporated into a planar membrane of known lipid composition and currents induced by M2 were measured by the Black Lipid Membrane technique. When the planar lipid bilayer was composed of 75% phosphatidylethanolamine and 25% phosphatidylserine, the reversal potential measured in a 150/600 mM KCl (cis/trans) gradient was -19 mV suggesting that the examined pore was preferential to anions, Pk/Pci = 0.25. In contrast, when 75% phosphatidylserine and 25% phosphatidylethanolamine was used, the reversal potential was +20 mV and the pore was preferential to cations, Pk/Pci = 4.36. Single-channel currents were recorded with two predominant amplitudes corresponding to the main-conductance and sub-conductance states. Both conductance states (about 12 pS and 30 pS) were measured in a symmetric solution of 50 mM KCl. The observed single-channel properties suggest that the selectivity and conductance of the pore formed by the M2 peptide of the glycine receptor depend on the lipid composition of the planar bilayer.

2

Bicuculline, AP-7 and behavioral activity in rats

80%

Car H., Kuziemka-Leska M., Wisniewski K.

Acta Neurobiologiae Experimentalis

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1998

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tom 58

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nr 2

3

Ion channels-related diseases

80%

Dworakowska B., Dolowy K.

Acta Biochimica Polonica

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2000

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tom 47

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nr 3

There are many diseases related to ion channels. Mutations in muscle voltage-gated sodium, potassium, calcium and chloride channels, and acetylcholine-gated channel may lead to such physiological disorders as hyper- and hypokalemic periodic paralysis, myotonias, long QT syndrome, Brugada syndrome, malignant hyperthermia and myasthenia. Neuronal disorders, e.g., epilepsy, episodic ataxia, familial hemiplegic migraine, Lambert-Eaton myasthenic syndrome, Alzheimer's disease, Parkinson's disease, schizophrenia, hyperekplexia may result from dysfunction of voltage-gated sodium, potassium and calcium channels, or acetylcholine- and glycine-gated channels. Some kidney disorders, e.g., Bartter's syndrome, policystic kidney disease and Dent's disease, secretion disorders, e.g., hyperinsulinemic hypoglycemia of infancy and cystic fibrosis, vision disorders, e.g., congenital stationary night blindness and total colour-blindness may also be linked to mutations in ion channels.

Ograniczanie wyników

2 Acta Biochimica Polonica

1 Acta Neurobiologiae Experimentalis

2 Dolowy K.

1 Bednarczyk P.

1 Car H.

1 Dworakowska B.

1 Kuziemka-Leska M.

1 Szewczyk A.

1 Wisniewski K.

1 2002

1 2000

1 1998

Transmembrane segment M2 of glycine receptor as a model system for the pore-forming structure of ion channels

Bicuculline, AP-7 and behavioral activity in rats

Ion channels-related diseases