Presynaptic and postsynaptic effects of the venom of the Australian tiger snake at the neuromuscular junction.
| Title: | Presynaptic and postsynaptic effects of the venom of the Australian tiger snake at the neuromuscular junction. |
|---|---|
| Authors: | Datyner ME; Gage PW |
| Source: | British journal of pharmacology [Br J Pharmacol] 1973 Oct; Vol. 49 (2), pp. 340-54. |
| Publication Type: | Journal Article |
| Language: | English |
| Journal Info: | Publisher: Wiley Country of Publication: England NLM ID: 7502536 Publication Model: Print Cited Medium: Print ISSN: 0007-1188 (Print) Linking ISSN: 00071188 NLM ISO Abbreviation: Br J Pharmacol Subsets: MEDLINE |
| Imprint Name(s): | Publication: London : Wiley; Original Publication: London, Macmillian Journals Ltd. |
| MeSH Terms: | Snakes*; Neuromuscular Junction/*drug effects ; Venoms/*pharmacology; Acetylcholine/pharmacology ; Action Potentials/drug effects ; Antivenins/pharmacology ; Carbachol/antagonists & inhibitors ; Chemoreceptor Cells/drug effects ; Membrane Potentials/drug effects ; Muscle Contraction/drug effects ; Neuromuscular Nondepolarizing Agents/pharmacology ; Receptors, Neurotransmitter/drug effects ; Tubocurarine/pharmacology ; Venoms/administration & dosage ; Animals ; Bufo marinus ; Calcium ; Computers ; Electric Stimulation ; Electrophysiology ; In Vitro Techniques ; Magnesium ; Microelectrodes |
| Abstract: | 1. Crude venom (TSV) from the Australian tiger snake (Notechis scutatus scutatus) has both presynaptic and postsynaptic effects at the neuromuscular junctions of toads.2. TSV (50 mug/ml) rapidly blocked indirectly elicited muscle twitches without affecting the compound action potential in the sciatic nerve or twitches elicited by direct stimulation.3. Low concentrations of the venom (1-10 mug/ml) reduced the amplitude of miniature endplate potentials (m.e.p.ps) and inhibited the depolarization of muscle fibres normally caused by carbachol. It was concluded that a fraction of the venom binds to acetylcholine receptors.4. The frequency of m.e.p.ps was at first increased by TSV at a concentration of 1 mug/ml. Occasional, high frequency ;bursts' of m.e.p.ps were recorded in some preparations. The mean frequency of m.e.p.ps appeared to fall after several hours in the venom.5. The quantal content of endplate potentials (e.p.ps) was reduced by the venom. With low concentrations (1 mug/ml), an initial increase in quantal content was often seen. When the quantal content was markedly depressed there was no parallel reduction in the amplitude of nerve terminal spikes recorded extracellularly, though a later fall in size and slowing of time course was often seen.6. There was evidence that TSV eventually changed the normal Poisson characteristics of the spontaneous release of quanta and this may be correlated with electronmicroscopic changes in nerve terminals.7. Tiger snake antivenene counteracted the postsynaptic, but not the presynaptic effects of TSV when they had developed. |
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| Substance Nomenclature: | 0 (Antivenins); 0 (Neuromuscular Nondepolarizing Agents); 0 (Receptors, Neurotransmitter); 0 (Venoms); 8Y164V895Y (Carbachol); I38ZP9992A (Magnesium); N9YNS0M02X (Acetylcholine); SY7Q814VUP (Calcium); W9YXS298BM (Tubocurarine) |
| Entry Date(s): | Date Created: 19731001 Date Completed: 19740917 Latest Revision: 20190511 |
| Update Code: | 20260130 |
| PubMed Central ID: | PMC1776377 |
| DOI: | 10.1111/j.1476-5381.1973.tb08381.x |
| PMID: | 4367126 |
| Database: | MEDLINE |
Journal Article