Black Widow Spider Neurotoxins
BilZ0r at TAKETHISOUThotmail.com
Sat Sep 18 19:20:55 EST 2004
curious11112001 at yahoo.com (Curious) wrote in
news:34a4f456.0409181256.22281d1d at posting.google.com:
> What symptoms would I experience if poisons from the Black Widow
> Spider was "fed" directly into the CNS neurons that make up my
> motor cortex?
What a very interesting toxin Black Widows have:
It would seem to me it would cause seizures.
Annu Rev Neurosci. 2001;24:933-62.
alpha-Latrotoxin and its receptors: neurexins and CIRL/latrophilins.
alpha-Latrotoxin, a potent neurotoxin from black widow spider venom,
triggers synaptic vesicle exocytosis from presynaptic nerve terminals.
alpha-Latrotoxin is a large protein toxin (120 kDa) that contains 22
ankyrin repeats. In stimulating exocytosis, alpha-latrotoxin binds to two
distinct families of neuronal cell-surface receptors, neurexins and CLs
(Cirl/latrophilins), which probably have a physiological function in
synaptic cell adhesion. Binding of alpha-latrotoxin to these receptors
does not in itself trigger exocytosis but serves to recruit the toxin to
the synapse. Receptor-bound alpha-latrotoxin then inserts into the
presynaptic plasma membrane to stimulate exocytosis by two distinct
transmitter-specific mechanisms. Exocytosis of classical
neurotransmitters (glutamate, GABA, acetylcholine) is induced in a
calcium-independent manner by a direct intracellular action of alpha-
latrotoxin, while exocytosis of catecholamines requires extracellular
calcium. Elucidation of precisely how alpha-latrotoxin works is likely to
provide major insight into how synaptic vesicle exocytosis is regulated,
and how the release machineries of classical and catecholaminergic
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