Accession Number:

AD0637845

Title:

STUDIES ON CARDIOTOXIN AND VASOACTIVE-SUBSTANCE-RELEASING COMPONENT(S) OF COBRA VENOM. I. PURIFICATION AND SOME PHARMACOLOGICAL PROPERTIES OF CARDIOTOXIN

Descriptive Note:

Corporate Author:

NATIONAL TAIWAN UNIV TAIPEI PHARMACOLOGICAL INST

Report Date:

1966-07-15

Pagination or Media Count:

36.0

Abstract:

Lyophylized venom of Naja naja atra was fractionated on column of CM-Sephadex G-50 into 13 fractions by gradient elution with ammonium acetate buffer at pH 5-7. Among them five fractions V-IX were found to be neurotoxic and three X,XII,XIII were cardiotoxic. Intraperitoneal LD50 in mice was 0.074 micrograms for Fr. VIII-the major neurotoxic component NT and 1.48 microgramsg for Fr.XIII-the major cardiotoxic one CT. CT caused contracture, as well as reduction of resting membrane potentials, of the frogs sartorius, chicks biventer cervicis, and rats diaphragm. In the absence of calcium, the contracture was markedly reduced, although the depolarizing effect remained unchanged. Neither contracture nor depolarization was caused by NT. The terminal nerve spikes of the frog sartorius were abolished by CT but unaffected by NT. CT caused systolic arrest of isolated frog hearts and rats atria by reducing the membrane potentials, whereas NT was almost without effect. CT caused a slow contraction of the guinea pig ileum, which was partially antagonized by either atropine or procaine but not by hexamethonium or antihistaminics. In the presence of CT, the responses to nicotine and 5-hydroxytryptamine were greatly inhibited, usually preceded by an initial and transient facilitation. The responses to histamine and acetylcholine were not, or only slightly, reduced by CT. The vessels of the rabbit ear were constricted by CT. Author

Subject Categories:

  • Toxicology
  • Pharmacology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE