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Dispersion of cumulus cells surrounding mice oocytes by stonefish (Synanceja horrida) venom hyaluronidase
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Tenth World Congress
The effects of the scorpion venom (Buthus tumulus) on neuromuscular transmission. H. VATANPOUR,E. G. ROWAN, A.L. HARVEY and P. GOPALAKRISHNAKONE (Department of Physiology and Pharmacology, Strathclyde University, 204 George Street, Glasgow G1 IXW, U.K.).
WE HAVE investigated the effects of the venom from the Indian red scorpion (Buthus tamulus, BT) on neuromuscular transmission in vitro. At 1 #g/ml, BT induced a 50% augmentation of the twitch responses of chick biventer cervicis preparations to indirect, but not direct, stimulation; at 3#g/ml, the augmentation was 300% after 60 min; and a 10 #g/ml, there was a transient augmentation followed by a contracture (about 160% of control twitch height) and a reduction in twitch height. The contracture was less than 30% in directly stimulated, tubocurarine-blocked preparations, and BT (I0 #g/ml) augmented twitch responses of directly stimulated preparations by less than 50°/0. BT (0.3-3 #g/ml) caused little change in postjunctional sensitivity as assessed by responses to exogenous acetylcholine, carbachol and KCI. BT (3-I 0/~g/ml) reversed partial blockade of indirect stimulation induced by tubocurarine, procaine and Mg 2+. On mouse hemidiaphragm preparations, BT (10#g/ml) produced greater augmentation of twitch responses to indirect stimulation (about 300%) than to direct stimulation (about 30%). In mouse triangularis sterni preparations, BT (3 and 10 #g/ml) increased quantal content of endplate potentials, without markedly affecting the time course, amplitude or frequency of miniature endplate potentials. BT also caused repetitive endplate potentials after single shock nerve stimulation. Perineural recording of nerve action potentials revealed that BT (10-30 #g/ml) also caused repetitive firing of nerve endings in response to single shock stimulation. Initially, the waveform remained unchanged after exposure to the venom; however, longer exposure results in the reduction in the amplitude of the second negative deflection (associated with K ÷ effiux from the terminals) and a marked prolongation in its time course. These results are consistent with BT acting mainly prejunctionally to increase the release of acetylcholine. The effects on the perineural waveforms suggest that some of its action may be due to disturbances in the activation or inactivation of sodium channels at or near the nerve terminals, or to blocking of potassium channels. We have demonstrated that BT inhibits dendrotoxin binding to synaptic membranes.
Conotoxins: interaction with neurotransmitter receptors and calcium channels. G. VAUQUELIN, P. PARTOENS, E. CZERWIEC, J. DE BLOCK, V. K. SAXENAand W. DE POTTER (Department of Protein Chemistry, Free University, Brussels (VUB); Department of Neuropharmacology, University of Antwerp (UIA), Belgium). CONIDAE, a family of tropical gastropods, use an elaborate venom apparatus to kill their prey: i.e. worms, other
molluscs and even fish. Venoms of different species contain large peptides (mol. wt > 10,000) which can bind with high affinity to N-type calcium channels and various 5-HT and catecholamine receptors, and even discriminate between receptor subtypes. Frozen Conidae are obtained from the Seychelles, the venom is removed from the venom duct, homogenized and sonicated in 33 mM ammonium acetate and centrifuged. The supernatant is used. The venom of C. distans contains a 25,000 mol. wt peptide which inhibits the electrically evoked noradrenaline release from rat hippocampal slices, apparently by competing with calcium for N-type voltage sensitive calcium channels. The venom of C. tessulatus prevents (in a calcium-dependent manner) radioligand binding to ~t2-adrenergic receptors in membrane preparations from calf-retina, but not from human brain. Instead, the venom interacts more avidly with 5-HTlA receptors as with ct2-receptors in brain. This venom also constitutes an elegant discriminatory tool between D1 and D2 dopaminergic receptors (calf retina). Active components will be purified, but even crude venoms already constitute potential tools for the biochemical investigation of ion channels and receptors.
Natural protoberberines and/or berberines in the cure of artificial hepatitis. P. VIRTANEN, L. JALANDER and V. LASSILA (Faculty of Medicine and Dentistry, Medical Cyclotron Lab., University of Turku, 20500 Turku, Finland).
AN ALKALOIDextract from Enantia chlorantha containing protoberberine alkaloids, palmatine, columbamine and jatrorrhizine has successfully been used to cure of jaundice in Cameroon folk medicine. In this study the composition of above-mentioned extracts was analysed again by gas chromatographic, NMR and capillary electrophoretic methods, and the potencies in the cure of D-galactosamine injured rats liver were recognized. According to our gas chromatographic and H-NMR analysis, the protoberberine alkaloid composition of E. chlorantha was: palmatine 63%, jatrorrhizine 19%, columbamine 8%, pseudocolumbamine 9% and xylopinine 1%. Recently processed capillary electrophoretic analysis showed, however, the above-mentioned protoberberine alkaloids were in balance with corresponding berberine alkaloids with a very delicate mechanism, which seems to be an essential factor both in therapy of D-galactosamine traumatized liver and in toxic properties of the mixture. The therapeutic and/or toxic effects of various mixtures were elavuated microscopically from liver biopsies, and also biochemically from serum. Both monitoring methods indisputably show that given in i.p. doses of 2 mg/kg/bw for a week, a certain alkaloid mixture of E. chlorantha both prevents the liver injuries
Tenth World Congress
The effects of the scorpion venom (Buthus tumulus) on neuromuscular transmission. H. VATANPOUR,E. G. ROWAN, A.L. HARVEY and P. GOPALAKRISHNAKONE (Department of Physiology and Pharmacology, Strathclyde University, 204 George Street, Glasgow G1 IXW, U.K.).
WE HAVE investigated the effects of the venom from the Indian red scorpion (Buthus tamulus, BT) on neuromuscular transmission in vitro. At 1 #g/ml, BT induced a 50% augmentation of the twitch responses of chick biventer cervicis preparations to indirect, but not direct, stimulation; at 3#g/ml, the augmentation was 300% after 60 min; and a 10 #g/ml, there was a transient augmentation followed by a contracture (about 160% of control twitch height) and a reduction in twitch height. The contracture was less than 30% in directly stimulated, tubocurarine-blocked preparations, and BT (I0 #g/ml) augmented twitch responses of directly stimulated preparations by less than 50°/0. BT (0.3-3 #g/ml) caused little change in postjunctional sensitivity as assessed by responses to exogenous acetylcholine, carbachol and KCI. BT (3-I 0/~g/ml) reversed partial blockade of indirect stimulation induced by tubocurarine, procaine and Mg 2+. On mouse hemidiaphragm preparations, BT (10#g/ml) produced greater augmentation of twitch responses to indirect stimulation (about 300%) than to direct stimulation (about 30%). In mouse triangularis sterni preparations, BT (3 and 10 #g/ml) increased quantal content of endplate potentials, without markedly affecting the time course, amplitude or frequency of miniature endplate potentials. BT also caused repetitive endplate potentials after single shock nerve stimulation. Perineural recording of nerve action potentials revealed that BT (10-30 #g/ml) also caused repetitive firing of nerve endings in response to single shock stimulation. Initially, the waveform remained unchanged after exposure to the venom; however, longer exposure results in the reduction in the amplitude of the second negative deflection (associated with K ÷ effiux from the terminals) and a marked prolongation in its time course. These results are consistent with BT acting mainly prejunctionally to increase the release of acetylcholine. The effects on the perineural waveforms suggest that some of its action may be due to disturbances in the activation or inactivation of sodium channels at or near the nerve terminals, or to blocking of potassium channels. We have demonstrated that BT inhibits dendrotoxin binding to synaptic membranes.
Conotoxins: interaction with neurotransmitter receptors and calcium channels. G. VAUQUELIN, P. PARTOENS, E. CZERWIEC, J. DE BLOCK, V. K. SAXENAand W. DE POTTER (Department of Protein Chemistry, Free University, Brussels (VUB); Department of Neuropharmacology, University of Antwerp (UIA), Belgium). CONIDAE, a family of tropical gastropods, use an elaborate venom apparatus to kill their prey: i.e. worms, other
molluscs and even fish. Venoms of different species contain large peptides (mol. wt > 10,000) which can bind with high affinity to N-type calcium channels and various 5-HT and catecholamine receptors, and even discriminate between receptor subtypes. Frozen Conidae are obtained from the Seychelles, the venom is removed from the venom duct, homogenized and sonicated in 33 mM ammonium acetate and centrifuged. The supernatant is used. The venom of C. distans contains a 25,000 mol. wt peptide which inhibits the electrically evoked noradrenaline release from rat hippocampal slices, apparently by competing with calcium for N-type voltage sensitive calcium channels. The venom of C. tessulatus prevents (in a calcium-dependent manner) radioligand binding to ~t2-adrenergic receptors in membrane preparations from calf-retina, but not from human brain. Instead, the venom interacts more avidly with 5-HTlA receptors as with ct2-receptors in brain. This venom also constitutes an elegant discriminatory tool between D1 and D2 dopaminergic receptors (calf retina). Active components will be purified, but even crude venoms already constitute potential tools for the biochemical investigation of ion channels and receptors.
Natural protoberberines and/or berberines in the cure of artificial hepatitis. P. VIRTANEN, L. JALANDER and V. LASSILA (Faculty of Medicine and Dentistry, Medical Cyclotron Lab., University of Turku, 20500 Turku, Finland).
AN ALKALOIDextract from Enantia chlorantha containing protoberberine alkaloids, palmatine, columbamine and jatrorrhizine has successfully been used to cure of jaundice in Cameroon folk medicine. In this study the composition of above-mentioned extracts was analysed again by gas chromatographic, NMR and capillary electrophoretic methods, and the potencies in the cure of D-galactosamine injured rats liver were recognized. According to our gas chromatographic and H-NMR analysis, the protoberberine alkaloid composition of E. chlorantha was: palmatine 63%, jatrorrhizine 19%, columbamine 8%, pseudocolumbamine 9% and xylopinine 1%. Recently processed capillary electrophoretic analysis showed, however, the above-mentioned protoberberine alkaloids were in balance with corresponding berberine alkaloids with a very delicate mechanism, which seems to be an essential factor both in therapy of D-galactosamine traumatized liver and in toxic properties of the mixture. The therapeutic and/or toxic effects of various mixtures were elavuated microscopically from liver biopsies, and also biochemically from serum. Both monitoring methods indisputably show that given in i.p. doses of 2 mg/kg/bw for a week, a certain alkaloid mixture of E. chlorantha both prevents the liver injuries