Analysis of paralytic shellfish poisoning toxin congeners by a sodium channel receptor binding assay

Gires Usup, Chui Pin Leaw, Mei Yee Cheah, Asmat Ahmad, Boon Koon Ng

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

This study was carried out to characterize the detection and quantitation of several paralytic shellfish poisoning (PSP) toxin congeners using a receptor binding assay (RBA). This involved competitive binding of the toxin congeners against tritium-labeled STX for receptor sites on rat brain sodium channels. Competitive binding curves were described by a four-parameter logistic equation. Half-saturation values (EC50) ranged from 4.38nM for STX to 142nM for GTX5. Receptor binding affinity was in the order STX>GTX1/ 4>neoSTX>GTX2/3>dcSTX>GTX5, and this was similar to the order of mouse toxicity of these congeners. Predicted toxin concentrations from observed STXeq values and EC50 ratios relative to STX were within 20% or better of the actual concentrations used in the assay. In contrast predicted toxin concentrations using mouse toxicity ratios relative to STX did not provide a good match to actual concentrations, except for GTX1/4. This study has shown that the rat brain sodium channel RBA will provide a reliable integration of total toxicity of various PSP toxin congeners present in a sample.

Original languageEnglish
Pages (from-to)37-43
Number of pages7
JournalToxicon
Volume44
Issue number1
DOIs
Publication statusPublished - Jul 2004

Fingerprint

Shellfish Poisoning
Shellfish
Competitive Binding
Sodium Channels
Toxicity
Assays
Tritium
Rats
Brain
Logistics

Keywords

  • Paralytic shellfish poisoning
  • Paralytic shellfish poisoning toxin detection
  • Receptor binding assay
  • Sodium channel

ASJC Scopus subject areas

  • Toxicology

Cite this

Analysis of paralytic shellfish poisoning toxin congeners by a sodium channel receptor binding assay. / Usup, Gires; Leaw, Chui Pin; Cheah, Mei Yee; Ahmad, Asmat; Ng, Boon Koon.

In: Toxicon, Vol. 44, No. 1, 07.2004, p. 37-43.

Research output: Contribution to journalArticle

Usup, Gires ; Leaw, Chui Pin ; Cheah, Mei Yee ; Ahmad, Asmat ; Ng, Boon Koon. / Analysis of paralytic shellfish poisoning toxin congeners by a sodium channel receptor binding assay. In: Toxicon. 2004 ; Vol. 44, No. 1. pp. 37-43.
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