魚類黒色素胞系に対するグラヤノトキシンの影響

　α-Dihydrograyanotoxin II (α-2H-GTX II) induced melanosome aggregation in the innervated melanophores of a teleost, Zacco temmincki, but not in the denervated ones. The effect of the toxin was inhibited by tetrodotoxin (TTX). It was concluded that α-2H-GTX II acted on the nerve to open Na-channels of the membrane, producing transmitter release from varicosities of the chromatic fiber. Since α-2H-GTX II and TTX did not affect responsiveness of melanophores to noradrenaline, it was argued that Na^+ inflow through the membrane did not participate drrectly in triggering pigment movements.