Tetanus toxin blocks the neuromuscular transmission in vitro like botulinum a toxin

1980 ◽  
Vol 311 (1) ◽  
pp. 33-40 ◽  
Author(s):  
E. Habermann ◽  
F. Dreyer ◽  
H. Bigalke
Keyword(s):  
Tetanus Toxin ◽  
Neuromuscular Transmission ◽  
Botulinum A Toxin

Synaptic and intrinsic control of membrane excitability of neostriatal neurons. II. An in vitro analysis

1990 ◽  
Vol 63 (4) ◽  
pp. 663-675 ◽  
Author(s):  
P. Calabresi ◽  
N. B. Mercuri ◽  
G. Bernardi
Keyword(s):  
Membrane Potential ◽  
Tetanus Toxin ◽  
Reversal Potential ◽  
Membrane Potentials ◽  
Synaptic Activity ◽  
Membrane Properties ◽  
Membrane Excitability ◽  
Epsp Amplitude ◽  
The Relationship

1. The effects of intrinsic membrane properties on the spontaneous and synaptically evoked activity of neostriatal neurons were studied in an in vitro slice preparation with the use of intracellular recordings. The recorded neurons did not show spontaneous action potentials at rest; depolarizing current pulses triggered a tonic firing pattern. 2. Subthreshold spontaneous depolarizing potentials (SDPs) were observed in 52% of the recorded neurons. The amplitude of these potentials at rest ranged between 2 and 15 mV, and their duration between 4 and 100 ms. The frequency and the amplitude of the SDPs were functions of the membrane potential: membrane depolarization by constant positive current increased the frequency of the SDPs and reduced their amplitude; hyperpolarization of the membrane decreased their frequency and increased their amplitude. Often, at membrane potentials more negative than -90 mV, SDPs were completely suppressed. 3. SDPs were blocked by low calcium-cobalt containing solutions. In the presence of tetrodotoxin (TTX, 1-3 microM), SDPs were completely abolished in 50% of the tested neurons; in the remaining neurons, small (1-4 mV) TTX-resistant SDPs were observed. In most of the neurons, bicuculline (BIC, 10-100 microM) and low concentrations of tetanus toxin (5-10 micrograms/ml) did not clearly affect the SDPs. Higher concentrations of tetanus toxin (100 micrograms/ml) blocked the SDPs as well as the synaptic potentials evoked by intrastriatal stimulation. 4. At resting membrane potential, intrastriatal stimulation produced a fast depolarizing postsynaptic potential (EPSP) that was reduced by BIC (10-100 microM). The relationship between EPSP amplitude and membrane potential was studied either by utilizing K(+)-chloride electrodes or by the use of cesium-chloride electrodes. In both these cases, the reversal potential for the EPSPs was between 0 and -14 mV. In cesium-loaded neurons, the decrease of the EPSP, usually observed at negative membrane potentials (below -85 mV), was clearly reduced. Internal cesium prolonged the duration of the SDPs and the EPSPs evoked by intrastriatal stimulation. 5. The relationship between spontaneous and evoked synaptic activity and membrane potential was studied in the presence of different external potassium blockers. 4-Aminopyridine (4AP, 0.1-1 mM) increased the EPSP amplitude and the frequency of the SDPs, but did not decrease membrane rectification and the shunt of the EPSPs present at negative membrane potentials. On the contrary, rectification of the membrane and the shunt of the EPSPs below -85 mV were clearly reduced by tetraethylammonium (TEA, 10-20 mM).(ABSTRACT TRUNCATED AT 400 WORDS)

Action of tetanus toxin on neuromuscular transmission

1964 ◽  
Vol 58 (4) ◽  
pp. 1199-1203
Author(s):  
G. N. Kryzhanovskii ◽  
A. Kh. Kasymov
Keyword(s):  
Tetanus Toxin ◽  
Neuromuscular Transmission

Platyhelminth FMRFamide-related peptides (FaRPs) contract Schistosoma mansoni (Trematoda: Digenea) muscle fibres in vitro

Parasitology ◽  
1994 ◽  
Vol 109 (4) ◽  
pp. 455-459 ◽  
Author(s):  
T. A. Day ◽  
A. G. Maule ◽  
C. Shaw ◽  
D. W. Halton ◽  
S. Moore ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Neuromuscular Transmission ◽  
Free Acid ◽  
Muscle Fibres ◽  
Channel Blockers ◽  
Excitatory Effect ◽  
Extracellular Medium ◽  
High K ◽  
Dose Dependent

SUMMARYMolluscan FMRFamide and two recently discovered platyhelminth FMRFamide-related peptides (FaRPs), GNFFRFamide from the cestode Moniezia expansa and RYIRFamide from the terrestrial turbellarian Artioposthia triangulata, cause dose-dependent contractions of individual muscle fibres from Schistosoma mansoni in vitro. The most potent FaRP tested was the turbellarian peptide RYIRFamide, which produced a concentration-dependent effect between 10−9 and 10−7 M. FMRFamide and GNFFRFamide were less potent, inducing contractions between 10−8–10−6 M and 10−7–10−5 M respectively. The contractile effect of each of these peptides was blocked by the presence of 1 µM FMR-DFamide. FMRF free acid did not elicit contraction of the muscle fibres. The FaRP-induced contractions did not occur if the Ca2+ was omitted and 0·5 µM EGTA was added to the extracellular medium. The FaRP-induced contractions were not blocked by the Ca2+ channel blockers nicardipine, verapamil or diltiazem, although high K+-induced contractions of these fibres were blocked by nicardipine. These data indicate the presence of FaRP receptors on schistosome muscle fibres and demonstrate their ability to mediate muscle contraction. The action of these endogenous flatworm peptides on schistosome muscle is the first demonstration of a direct excitatory effect of any putative neurotransmitter on the muscle of a flatworm, and establishes a role for FaRPs in neuromuscular transmission in trematodes. In addition, it provides the first evidence that the peptidergic nervous system is a rational target for chemotherapeutic attack in parasitic platyhelmiths.

Effects of scorpion (Buthus tamulus) venom on neuromuscular transmission in vitro

Toxicon ◽  
1993 ◽  
Vol 31 (11) ◽  
pp. 1373-1384 ◽  
Author(s):  
H. Vatanpour ◽  
E.G. Rowan ◽  
A.L. Harvey
Keyword(s):  
Neuromuscular Transmission
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