Synthesis of the Photoaffinity-labeled Grayanotoxins for Studying the Gating Mechanism of Na Channel.
Grayanotoxin loosely binds to the neurotoxin receptor site 2 on Na channels. 14R-N-[4-(1-Azi-2, 2, 2-triftuoroethyl)]benzyliminograyanotoxane-3β, 5, 6β, 16-tetraol (4) and 17-N-[4-(1-azi-2, 2, 2-triftuoroethyl)]- benzyliminograyanotox-15-ene-3β, 5, 6β, 14R-tetraol (5) were synthesized and applied intracellularly to squid axons. On UV irradiation, their membrane potential produced by a dose of 4 or 5 rose to higher level than that in the dark. However, in the case of 5, even when the axons were internally perfused with toxin-free solution after the dose, the potential level did not fall in contrast to 4. It suggested that 5 covalently bound to the receptor involved in the gating mechanism of Na channels.
a Bioresources Chemistry, Faculty of Agriculture , Okayama University , Tsushima-naka , Okayama 700 , Japan.
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Iwasa
a Bioresources Chemistry, Faculty of Agriculture , Okayama University , Tsushima-naka , Okayama 700 , Japan.
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Kamano
a Bioresources Chemistry, Faculty of Agriculture , Okayama University , Tsushima-naka , Okayama 700 , Japan.|b Department of Physiology , School of Medicine, Hiroshima University , Kasumi, Minami-ku , Hiroshima 734 , Japan.
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Tsuji
a Bioresources Chemistry, Faculty of Agriculture , Okayama University , Tsushima-naka , Okayama 700 , Japan.|b Department of Physiology , School of Medicine, Hiroshima University , Kasumi, Minami-ku , Hiroshima 734 , Japan.
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Seyama
a Bioresources Chemistry, Faculty of Agriculture , Okayama University , Tsushima-naka , Okayama 700 , Japan.
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Baba
a Bioresources Chemistry, Faculty of Agriculture , Okayama University , Tsushima-naka , Okayama 700 , Japan.
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Nakajima