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SEPARATION OF NEUROTOXINS FROM HORNET (VESPA INSULARIS) VENOM AND THEIR ACTIONS ON CRUSTACEAN NEUROMUSCULAR TRANSMISSION
Author(s) -
Hori S.,
Kawai N.,
Niwa A.,
Ohotani S.
Publication year - 1977
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1977.tb12307.x
Subject(s) - postsynaptic potential , excitatory postsynaptic potential , sephadex , inhibitory postsynaptic potential , carboxypeptidase a , neuromuscular transmission , carboxypeptidase , biology , neurotransmission , chymotrypsin , trypsin , biophysics , venom , biochemistry , neuroscience , enzyme , endocrinology , receptor
— The venom of homet ( Vespa insularis) was separated into three components by gel filtration on Sephadex G‐50, Sephadex G‐25 and Sephadex G‐10. The effect of each component on crustacean neuromuscular junctions was studied electrophysiologically using intracellular recordings. Two components (Fractions D and E) suppressed the postsynaptic potentials; Fraction D preferentially depressed excitatory postsynaptic potentials (epsps) without affecting inhibitory postsynaptic potentials (ipsps), and fraction E depressed both epsps and ipsps with concurrent decrease in membrane resistance. Another component (fraction F) augmented both epsps and ipsps. Fractions D and F were possibly acting presynaptically while fraction E was acting on the postsynaptic membrane. The active substances in fraction D, E and F were separated on TLC and the active substance in fraction F was confirmed to be serotonin. The active substances in fractions D and E are assumed to be peptides from the results of peptidase digestion. The effect of fraction D was degraded by treatment with trypsin but not by chymotrypsin nor carboxypeptidase A and B. On the other hand, the effect of fraction E was degraded by chymotrypsin and carboxypeptidase B but not by trypsin nor carboxypeptidase A.