Saxitoxin Binding in Nerves from Walking Legs of the Lobster Homarus americanus Two Classes of Receptors
نویسنده
چکیده
I N T R O D U C T I O N Saxi toxin (STX) and te t rodotoxin ( T T X ) are small organic molecules tha t specificially block sodium channels in m a n y exci table membranes . T h e physical chemical propert ies o f the receptor for S T X and T T X have been s tudied in bo th electrophysiological exper iments and in b ind ing exper iments with rad io labe led toxins. Earl ier results revealed s t rong similarities be tween the propert ies of the toxin receptor and o f the conduc tance o f open sodium channels; for example , bo th toxin b inding and sodium co n d u c t an ce were blocked by protons at p H 5.2-5.4, by calcium ions, and by thal lous ions (Co lquhoun et al., 1972; Hender son et al., 1973 and 1974; Hille, 1968 b, Woodhul l , 1973). T h e blocking act ion of T T X was also reduced by acidic J. GEN. PHYSIOL. ~) T he Rockefeller Universi ty Press 9 0022-1295/81/02/0205/17 $1.00 205 Volume 77 February1981 205-221 on Jne 9, 2017 D ow nladed fom Published February 1, 1981
منابع مشابه
Saxitoxin binding in nerves from walking legs of the lobster Homarus americanus. Two classes of receptors
The binding of exchange-labeled saxitoxin (STX) to sodium channels has been investigated in the nonmyelinated fibers of the walking leg nerves of the lobster. The properties of the STX binding site differed systematically among the nerves from different walking legs. The equilibrium dissociation constant for STX binding (KSTX) to the front legs is approximately twice that for the binding to the...
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