Some characteristics of end-plate potentials after partial blockade by α-bungarotoxin in Rana...
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DRVnert, W . F ., HwRV>.nr, A. L. and M" a` ~ + " ~ ~ ,1 . G. (Department of Physiology and Pharma- cology,University of Strathclyde, George Street, GlasgowGI 1XW, Scotland) . Phartnawlogical studies on the bungarotoxins : separatton of the fractions and their neuromuscular activity. Eur . J . Phar)nac . 26, 256, 1974. i9turgarus »talticinctus venom was separated into 13 fractions by column chromatography on CM-Sephadex C-S0 . These fractions were tested on the responses of the chick biventer cervicis preparation to nerve stimu- lation, and to acetylcholine and carbachol. One was inactive, four exhibited weak postjunctional neuro- muscular blocking activity, three had potent postjunctional blocking activity, and the remaining Sve fractions exhibited predominant prejunctional activity. Two of them also possessed some postjunctional blocking activity, probably due to incomplete separation . In general, these results are in agreement with those of LEE et al. (J. Chrornatogr . 72, 71, 1972) . The authors stress the importance that, when using venom components as experimental tools, the separation method should be detailed and the fractions thoroughly tested, because small differences in conditions may result in differences in the elution patterns of the venom . C .Y .L . Mess, D. (Zentrum der Rechtsmedizin, Klinikum der Universität Frankfurt a. M. ; Germany) . Chemistry of animal venoms, poisons and toxins . Experientia 29, 1328, 1973 . THE PAPER presents data according to the zoological taxonomy . A lucid arrangement shows the structures of potent and less potent nonpeptide toxins from nereistoxin to the amphibi-toxins. Active peptides are considered in a spetaal table as well as in a diagram of snake neurotoxins, emphasizing the function-related amino acids. The article supports the paper by Karlsson on animal toxins in the same issue . H.M . VYSKOCIL, F . and M~aezexa~, L . G. (Czechoslovak Academy of Science, Institute of Physio logy, Prague 4, Czechoslovakia). Temperature dependence of Naja toxin blacking effect in Rang ternporarta . Experientfa 29, 158, 1973 . CtuttncrERtsrres of the interaction of NaJa toxin (NaJa TX) with the cholinergic membranes of nerve muscle junctions were studied in terms of the effect of temperature, and in comparison with the binding of o-tubo curarine (nTC) . Sattorius muscles partly blocked with 12 M MgCI, were mounted for measurement of EPPs . In the presence of 10''v/w Ngja TX the T} decays of EPP amplitude of 3~0, l9ß and 43 " 0 min at three temperatures, 24, 12 and 2° imply an activation energy of binding of 3 " 4 kcal/mol . This is less than for a covalent bond but more than for Simple ionic binding. When the muscle is bathed in 2 " 5, 5 or 8x 10'' MdTC, the EPP amplitude reduction is the same at each of the three temperatures . Thus, the toxin reaction with the receptor is more complex than is the ionic binding of ACh. B.C .A . MAGAZANIK, L. G . and VYSICOCn., F. (Secheaov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences, Leningrad, U.S.S .R .) . Some chacactenstics of end-plate potentials after partial blockade by a-bungarotoxin in Rana temporarta. ExptrlenNa 29, 157,1973 . CH~Lt~xGES are made to the EPP profile and to the reversal potential with curare and atropine in frog sartorius preparations partially blocked by BuTX. The time course of EPP was unchanged by BuTX nor by added dTC, but the decay was speeded by AS . The reversal potential (E,) at -16 mV was unchanged by BuTX. However, an anomaly was found in the effect of K level on E, . In the presence of dTC, E, moved from -14 mV at 2 " 5 mM K to -27 mV at 0 " 5 mM K, whereas with BuTX it remained at -16 mV for both K levels . Kwwar, N., M~uRO, A. and GRUrmtrESr, H. (Metropolitan Institute for Neurosciences, Fuchu-City, Tokyo, Japan) . Effect of black widowspider venom on the lobster neuromuscular junctions . J. gen. Physlol. 60, 650, 1972 . TOXICON 1973 VoJ. 13 B.C .A . Trta Et=recr of black widow spider venom (BWSV) on the junctions of the lobster nerve-muscle preparation was studied by intracellular recordings . After application of BWSV both excitatory and inhibitory post-
Transcript of Some characteristics of end-plate potentials after partial blockade by α-bungarotoxin in Rana...
DRVnert, W. F., HwRV>.nr, A. L. and M"a`~+"~ ~ ,1 . G. (Department of Physiology and Pharma-
cology,UniversityofStrathclyde, GeorgeStreet, GlasgowGI 1XW, Scotland) . Phartnawlogicalstudies on the bungarotoxins: separatton of the fractions and their neuromuscular activity.
Eur . J . Phar)nac. 26, 256, 1974.
i9turgarus »talticinctus venom was separated into 13 fractions by column chromatography on CM-SephadexC-S0. These fractions were tested on the responses of the chick biventer cervicis preparation to nerve stimu-lation, and to acetylcholine and carbachol. One was inactive, four exhibited weak postjunctional neuro-muscular blocking activity, threehadpotent postjunctional blocking activity, and the remaining Sve fractionsexhibited predominant prejunctional activity. Two of them also possessed some postjunctional blockingactivity, probably due to incomplete separation . In general, these results are in agreement with those ofLEE et al. (J. Chrornatogr . 72, 71, 1972) .
The authors stress the importance that, when using venom components as experimental tools, theseparation method should be detailed and the fractions thoroughly tested, because small differences inconditions may result in differences in the elution patterns of the venom.
C.Y.L .
Mess, D. (Zentrum der Rechtsmedizin, Klinikum der Universität Frankfurt a. M. ; Germany) .Chemistry of animal venoms, poisons and toxins . Experientia 29, 1328, 1973 .
THE PAPER presents data according to the zoological taxonomy . A lucid arrangement shows the structuresof potent and less potent nonpeptide toxins from nereistoxin to the amphibi-toxins. Active peptides areconsidered in a spetaal table as well as in a diagram ofsnake neurotoxins, emphasizing the function-relatedamino acids. The article supports the paper by Karlsson on animal toxins in the same issue.
H.M .
VYSKOCIL, F . and M~aezexa~, L. G. (Czechoslovak Academy of Science, Institute of Physiology, Prague 4, Czechoslovakia). Temperature dependence of Naja toxin blacking effect in
Rang ternporarta. Experientfa 29, 158, 1973 .
CtuttncrERtsrres of the interaction of NaJa toxin (NaJa TX) with the cholinergic membranes of nervemuscle junctions were studied in terms of the effect of temperature, and in comparison with the binding ofo-tubo curarine (nTC). Sattorius muscles partly blocked with 12 M MgCI, were mounted for measurementof EPPs . In the presence of 10''v/w Ngja TX the T} decays of EPP amplitude of 3~0, l9ß and 43 "0 min atthree temperatures, 24, 12 and 2° imply an activation energy of binding of 3 "4 kcal/mol . This is less thanfor a covalent bond but more than for Simple ionic binding. When the muscle is bathed in 2 " 5, 5 or 8 x 10''MdTC, the EPP amplitude reduction is the same at each of the three temperatures . Thus, the toxin reactionwith the receptor is more complex than is the ionic binding of ACh.
B.C.A .
MAGAZANIK, L. G. and VYSICOCn., F. (Secheaov Institute of Evolutionary Physiology andBiochemistry, Academy of Sciences, Leningrad, U.S.S.R .) . Some chacactenstics of end-platepotentials after partial blockade by a-bungarotoxin in Rana temporarta. ExptrlenNa 29,
157,1973 .
CH~Lt~xGES are made to the EPP profile and to the reversal potential with curare and atropine in frogsartorius preparations partially blocked by BuTX. The time course of EPPwas unchanged by BuTX nor byadded dTC, but the decay was speeded by AS . The reversal potential (E,) at -16 mV was unchanged byBuTX. However, an anomaly was found in the effect of K level on E, . In the presence of dTC, E, movedfrom -14 mV at 2 "5mMKto -27 mV at 0 "5mM K, whereas with BuTX it remained at -16 mV for bothK levels .
Kwwar, N., M~uRO, A. and GRUrmtrESr, H. (Metropolitan Institute for Neurosciences,Fuchu-City, Tokyo, Japan) . Effect of black widowspider venom on the lobster neuromuscular
junctions . J. gen. Physlol. 60, 650, 1972 .
TOXICON 1973 VoJ. 13
B.C.A .
Trta Et=recr of black widow spider venom (BWSV) on the junctions of the lobster nerve-muscle preparationwas studied by intracellular recordings . After application of BWSV both excitatory and inhibitory post-
