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Intraspecies individual variability in the composition of Echis carinatus venom
Abstracts of Papers
529
aspartic and glutamic acid. Toxic protein contained no cysteine. The Loan determined in rats was 33-3 1Ag/kg when injected intravenously. From our experiments it can be concluded that the toxin affects the CNS. Animals appear to die due to arrest of respiration. In vitro, the toxin causes direct hemolysis of red blood cells.
(Istituto Superiore di SanitA, Rome, Italy). Studies on the mechanism of action of Latrodectus venom.
N. FRONTALL
Addition of an extract of Latrodectus mactans tredecinrguttatus venom glands to rat cerebral cortex slices in vitro is followed by increased release of acetylcholine, while the acetylcholine content of the tissue is correspondingly lowered. These and other findings (FRONTALi, et al., 1972) support the hypothesis that the venom affects the mechanism of transmitter release from cholinergic nerve endings, as has been supposed on the basis of electrophysiological and ultrastructural work on frog muscle end-plates (LONGENECKER et al., 1970 ; CLARK et al., 1970). In order to find out if other types of nerve endings are similarly affected, the venom has been assayed in vitro on rat iris (FRONTAL4 1972) and other rat tissues, where adrenergic nerve terminals and their catecholamine depletion are studied by means of fluorescence histochemistry. The results, which pointto an involvement of this type of nerve ending, are discussed in relation to the symptoms of latrodectism . REFERENCES FRoNTAtt, N., GRANATA, F. and PARLsi, P. (1972) Biochem. Pharmacol. 21, in press. LoNGENECKER, H. E. JR ., HURLBUT, W. P., MAuRo, A. and CLARK, A. W. (1970) Nature, Lond. 225, 701. CLARK, A.W., MAURo,A.,LoNGENECKER, H. E. JR . and HURLBUT, W. P. (1970) Nature, Lond. 225, 703. FRoNTALi, N. (1972) Brain Research 37, 146.
(Institute for Pathophysiology, Charles University, Prague, Czechoslovakia) . Intraspecies individual variability in the composition of Echis carinatus venom.
F. KORNAUK, E. TABoRsKA .
Twenty adult specimens of Echis carinates, captured near Karachi, were kept under identical conditions and individually milked twice a month for over a year and the respective venom samples submitted to analysis. There were found substantial differences in the disc-electrophoretic patterns and in the activities of 1-aminoacid oxidase and phospholipase A. In other enzymes investigated (e .g. phosphodiesterase, 5' nucleotidase, caseinolytic protease) no significant variations could be detected. The greatest individual variability was found in the in vitro thromboplastic andfibrinogenolytic enzymes and particularly in the in vivo defibrinating potencies of the venoms. Hereditary aspects as well as significance of these findings for antivenom production are discussed.
R. G. LA GRANGE . (Bowman Gray School of Medicine ofWake Forest University, WinstonSalem, N.C., U.S.A .). Mode of action of a scorpion neurotoxin . The venom from the scorpion, Centruroides sculpturatus, was studied on isolated preparations of frog sartorius muscle-nerve and sciatic nerve. guinea pig phrenic nerve-diaphragm and the crayfish medial giant axon . Results with the sartorious muscle-nerve (microelectrode recording) and phrenic nerve-diaphragm (elicited muscular response) give strong evidence that the venom acts through facilitation of releases of ACh at the neuromuscular junction by normal action potentials in the nerve fibre. The sciatic nerve action potential was unaffected, suggesting no action of the venomon long axis of the nerve; however, these results were contradicted by study of the crayfish medial giant axon (internal stimulation and recording) in which theelicited response became repetitive following venom application, although restingmembrane potential was essentially unaffected during the period of hyperexcitability . Following this phase there was a rapid decline in excitability accompanied by a membrane depolarization . The significance of results with the crayfish axon will be presented in relation to the other findings. TOXICON 1972 Vot. 10.
529
aspartic and glutamic acid. Toxic protein contained no cysteine. The Loan determined in rats was 33-3 1Ag/kg when injected intravenously. From our experiments it can be concluded that the toxin affects the CNS. Animals appear to die due to arrest of respiration. In vitro, the toxin causes direct hemolysis of red blood cells.
(Istituto Superiore di SanitA, Rome, Italy). Studies on the mechanism of action of Latrodectus venom.
N. FRONTALL
Addition of an extract of Latrodectus mactans tredecinrguttatus venom glands to rat cerebral cortex slices in vitro is followed by increased release of acetylcholine, while the acetylcholine content of the tissue is correspondingly lowered. These and other findings (FRONTALi, et al., 1972) support the hypothesis that the venom affects the mechanism of transmitter release from cholinergic nerve endings, as has been supposed on the basis of electrophysiological and ultrastructural work on frog muscle end-plates (LONGENECKER et al., 1970 ; CLARK et al., 1970). In order to find out if other types of nerve endings are similarly affected, the venom has been assayed in vitro on rat iris (FRONTAL4 1972) and other rat tissues, where adrenergic nerve terminals and their catecholamine depletion are studied by means of fluorescence histochemistry. The results, which pointto an involvement of this type of nerve ending, are discussed in relation to the symptoms of latrodectism . REFERENCES FRoNTAtt, N., GRANATA, F. and PARLsi, P. (1972) Biochem. Pharmacol. 21, in press. LoNGENECKER, H. E. JR ., HURLBUT, W. P., MAuRo, A. and CLARK, A. W. (1970) Nature, Lond. 225, 701. CLARK, A.W., MAURo,A.,LoNGENECKER, H. E. JR . and HURLBUT, W. P. (1970) Nature, Lond. 225, 703. FRoNTALi, N. (1972) Brain Research 37, 146.
(Institute for Pathophysiology, Charles University, Prague, Czechoslovakia) . Intraspecies individual variability in the composition of Echis carinatus venom.
F. KORNAUK, E. TABoRsKA .
Twenty adult specimens of Echis carinates, captured near Karachi, were kept under identical conditions and individually milked twice a month for over a year and the respective venom samples submitted to analysis. There were found substantial differences in the disc-electrophoretic patterns and in the activities of 1-aminoacid oxidase and phospholipase A. In other enzymes investigated (e .g. phosphodiesterase, 5' nucleotidase, caseinolytic protease) no significant variations could be detected. The greatest individual variability was found in the in vitro thromboplastic andfibrinogenolytic enzymes and particularly in the in vivo defibrinating potencies of the venoms. Hereditary aspects as well as significance of these findings for antivenom production are discussed.
R. G. LA GRANGE . (Bowman Gray School of Medicine ofWake Forest University, WinstonSalem, N.C., U.S.A .). Mode of action of a scorpion neurotoxin . The venom from the scorpion, Centruroides sculpturatus, was studied on isolated preparations of frog sartorius muscle-nerve and sciatic nerve. guinea pig phrenic nerve-diaphragm and the crayfish medial giant axon . Results with the sartorious muscle-nerve (microelectrode recording) and phrenic nerve-diaphragm (elicited muscular response) give strong evidence that the venom acts through facilitation of releases of ACh at the neuromuscular junction by normal action potentials in the nerve fibre. The sciatic nerve action potential was unaffected, suggesting no action of the venomon long axis of the nerve; however, these results were contradicted by study of the crayfish medial giant axon (internal stimulation and recording) in which theelicited response became repetitive following venom application, although restingmembrane potential was essentially unaffected during the period of hyperexcitability . Following this phase there was a rapid decline in excitability accompanied by a membrane depolarization . The significance of results with the crayfish axon will be presented in relation to the other findings. TOXICON 1972 Vot. 10.