Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 312 (1980), S. 255-263 
    ISSN: 1432-1912
    Keywords: Acetylcholine ; Tetanus toxin ; Botulinum toxin ; Myenteric plexus ; Transmitter release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of tetanus and botulinum A toxin were studied on the electrically stimulated myenteric plexus-ileum strip of the guinea pig. The concentrations used were in the range of 104–106 mouse LD50/ml. 1. Tetanus and botulinu, A toxin slowly decrease the amplitude of the contractile response to field stimulation in a dose-dependent manner without influencing the sensitivity to acetylcholine of the smooth muscle. 2. Development of paralysis is preceded by a latent period. Washing and antitoxin slow the paralytic process only when applied during the latent period. 3. The time course of development of paralysis depends on the activity of the strip. It can be slowed by rest, high [Mg2+], or low [Ca2+], and accelerated by raising the stimulation frequency. 4. Substances like 4-aminopyridine, sea anemone toxin II and scorpion toxin which prolong the membrane depolarization restore temporarily the contraction of partially paralysed muscle strips. 5. Poisoned preparations do not differ from controls in their total acetylcholine contents, whereas formation as well as release of [3H]-acetylcholine are decreased by either toxin. It is concluded that a) tetanus toxin and botulinum A toxin are qualitatively indistinguishable with respect to their actions on the postganglionic cholinergic neurons in the ileum, botulinum A toxin being 5 times more potent than tetanus toxin, b) the effects of the toxins at postganglionic cholinergic neurons in the ileum and at motor nerve endings are qualitatively similar, botulinum A toxin being about 500 times more potent than tetanus toxin at the latter preparation (see Habermann et al., 1980b, c) both toxins influence the turnover of acetylcholine but not its tissue concentration.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 316 (1981), S. 143-148 
    ISSN: 1432-1912
    Keywords: Tetanus toxin ; Botulinum toxin ; Acetylcholine ; Calcium ; Brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Slices or particles from rat forebrain cortex were preloaded with [3H]choline, and the release of [3H]acetylcholine was evoked with potassium ions in a superfusion system. Release depended on the presence of calcium. 1. Incubation of the preloaded tissue preparation for 2 h with tetanus or botulinum A toxin did not change the [3H]acetylcholine content or the ratio [3H]acetylcholine/[3H]choline. Tetanus toxin diminished, dependent on dose and time, the release of [3H]acetylcholine evoked by 25 mM K+. It was about ten times more potent than botulinum A toxin. The effect of botulinum toxin was due to its neurotoxin content. Raising the potassium concentration partially overcame the inhibition by the toxins. Hemicholinium-3, applied to preloaded slices, left the subsequent [3H]acetylcholine release unchanged. Pretreatment of particles with neuraminidase diminished the content of long-chain gangliosides to the detection limit. Such particles remained fully sensitive to tetanus toxin, and at least partially sensitive to botulinum A toxin. 2. The potassium or sea anemone toxin II stimulated uptake of 45Ca2+ into cortex synaptosomes or particles was not inhibited by either toxin. Both toxins appear to impede the Ca2+-dependent mobilization of an easily releasable acetylcholine pool, without inhibiting the transmembranal calcium fluxes.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 311 (1980), S. 33-40 
    ISSN: 1432-1912
    Keywords: Tetanus toxin ; Botulinum toxin ; Neuromuscular junction ; Calcium ; Neuraminidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The blocking effect of tetanus toxin on the neuromuscular junction of the mouse phrenic nervehemidiaphragm preparation exposed to the toxin (0.05–20 μg/ml) in the organ bath was studied and compared with the action of botulinum A toxin. 2. The time course of the paralysis of the diaphragm could be divided into a latent and a manifest period. Still during the latent period the effect of the toxin became progressively resistant to washing and, with some delay, to antitoxin. 3. Between 25 and 41°C the time until paralysis strongly depended on temperature with Q 10 of about 2.7. 4. Procedures increasing the transmitter release shortened, and procedures depressing it prolonged the time until paralysis. 5. 4-Aminopyridine and guanidine temporarily restored the contraction of the partially paralyzed diaphragm, indicating the persistence of activatable calcium and acetylcholine pools. Raising the external Ca2+-concentration and application of the Ca-Ionophore A 23187 were ineffective in the doses applied. 6. About 80 min after exposure to the toxin (10 μg/ml), the m.e.p.p. activity decreased by a factor of 30. Parallel to this, paralysis of nerve evoked muscle contraction developed. 7. Neuraminidase treatment did not prevent tetanus toxin poisoning. 8. The paralysis is produced by tetanus toxin itself and not by contaminants as shown by the parallel decrease of toxicity and paralysis following treatment with either antitoxin or brain homogenate, or by the use of spontaneously inactivated toxin. 9. Tetanus toxin was compared with botulinum A toxin as to the shape of its dose-response curve, time course of paralysis, temporary reversal by 4-aminopyridine and behaviour against Ca-ionophore. In any case, both toxins were indistinguishable, albeit botulinum A neurotoxin was calculated to be about 2000 times more potent than tetanus toxin.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...