Argiopine blocks glutamate-activated single-channel currents on crayfish muscle by two mechanisms.

The Journal of Physiology
S M AntonovH Hatt

Abstract

1. The effect of the spider venom argiopine on L-glutamate-activated membrane channels of crayfish muscle was investigated using the patch-clamp technique. 2. When 10(-2) M-glutamate and 10(-9) M-argiopine were contained in the pipette solution of a cell-attached patch, bursts of openings of excitatory channels appeared after formation of the patch. These bursts ceased abruptly after variable periods of time in the range of 5 min. Higher concentrations of argiopine (up to 10(-6) M) blocked more rapidly, approximately in proportion to concentration. 3. The block of excitatory channels could be partially or completely reversed by hyperpolarizing the membrane by up to -190 mV from the resting potential. The time constant of the recovery of channel opening decreased with increasing hyperpolarization and was 2 ms with -160 mV hyperpolarization. Switching back from the hyperpolarized level to the resting potential, the time constant for the resulting block was about 3 s (10(-7) M-argiopine). Potential-dependent block by argiopine with similar characteristics was also observed in outside-out patches. 4. Up to argiopine concentrations of 10(-7) M the kinetics of channel openings and of bursts measured in pre-block periods or during rev...Continue Reading

Citations

May 23, 1998·The Journal of Physiology·R Bähring, M L Mayer
Mar 1, 1992·Toxicon : Official Journal of the International Society on Toxinology·I S BlagbroughP N Usherwood
Apr 7, 2004·Toxicon : Official Journal of the International Society on Toxinology·Ian R Mellor, Peter N R Usherwood
Nov 1, 1991·Pharmacology & Therapeutics·P N Usherwood, I S Blagbrough
Jun 30, 2004·Medicinal Research Reviews·Kristian Strømgaard, Ian Mellor
Mar 10, 2010·Biochemistry. Biokhimii︠a︡·A A VassilevskiE V Grishin
Jan 1, 1995·Invertebrate Neuroscience : in·H L SudanP N Usherwood

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