Zinc ion enhances the blocking potency of synthetic analogs of spider toxin (JSTX) on the glutamate receptor.
The effect of synthetic spider toxin analogs containing aza-crown in combination with zinc and copper was studied on the lobster neuromuscular synapse. The suppressive action of N4-type spider toxin analog (N4) on excitatory postsynaptic potentials (EPSPs) was markedly enhanced in the presence of 10(-5)-10(-4) M Zn2+. Cu2+ (10(-4) M) also had a potentiating effect on the suppression of EPSPs by N4 but to a lesser degree than Zn2+. While N6-type spider toxin analog (N6) suppressed EPSPs more effectively than N4, additional suppression was not pronounced in the presence of Zn2+ or Cu2+. The results suggest that chelatable divalent metal ions play an important role in the blocking mechanism of glutamate receptor by the spider toxin.
Kawai
N
N
Department of Neurobiology, Tokyo Metropolitan Institute for Neurosciences, Japan.
Miwa
A
A
Hashimoto
Y
Y
Shudo
K
K
Asami
T
T
Nakajima
T
T
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001180:Arthropod Venoms / Q000494:pharmacology*; D003300:Copper / Q000494:pharmacology; D008121:Nephropidae; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology*; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology*; D013111:Spider Venoms / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000494:pharmacology*; D015032:Zinc / Q000494:pharmacology*
D001180:Arthropod Venoms; C044936:JSTX spider toxin; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D013111:Spider Venoms; D003300:Copper; D015032:Zinc