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  • Botulinum toxin  (3)
  • Kidney  (3)
  • 1
    Electronic Resource
    Electronic Resource
    The renal handling of polybasic drugs (1977)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 300 (1977), S. 67-76 
    Details
    ISSN: 1432-1912
    Keywords: Polycations ; Aminoglycosides ; Kidney ; Brush border membrane ; Lysosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Experiments with Brush Border Membranes Drugs were screened for inhibition of 125I-aprotinin binding to isolated rat renal brush border membranes. Cationic polymers were effective, and their primary amino groups were crucial. The polycationic aminoglycosides displaced 125I-aprotinin with low concentrations (50% inhibition by 50 μg/ml of gentamicin). The decreasing sequence of both number of amino groups and of inhibitory potency was: neomycin 〉 tobramycin 〉 gentamicin 〉 kanamycin 〉 streptomycin. Binding of 3H-gentamicin-C1 to the brush border membrane was saturable. The Scatchard plot indicated an association constant of 43 mM−1, and 18 nmoles per mg of membrane protein for the number of binding sites. Inhibition of 125I-aprotinin binding by gentamicin was competitive. The inhibition constant (KI) was 20 μg/ml with concentrations of 8 and 40 μg/ml of gentamicin. 2. Experiments with Lysosomes Gentamicin and aprotinin (200 μg/ml) activated β-glucuronidase and β-galactosidase from renal lysosomes, but not acid phosphatase. Gentamicin and aprotinin (300 μg/ml) increased the release of acid phosphatase from intact renal lysosomes. Lysosomal degradation of 125I-aprotinin into acid soluble split products was much slower than that of 125I-insulin. From our present and previous results it is concluded that binding to the brush border membrane occurs with chemically quite different, however basic drugs and that the number of amino groups per molecule is relevant. Nephrotoxicity of aminoglycosides may be related to their endocytic uptake through a direct action on lysosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00505081
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  • 2
    Electronic Resource
    Electronic Resource
    The renal handling of polybasic drugs (1977)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 300 (1977), S. 57-66 
    Details
    ISSN: 1432-1912
    Keywords: Aminoglycoside ; Gentamicin ; Kidney ; Electron microscopic autoradiography ; Lysosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Upon intravenous injection of 3H-gentamicin in rats, radioactivity in serum rapidly declined to 3% of total within 1 h. Kidneys accumulated a constant amount (14%) of the injected radioactivity between 2 and 6 h after injection. In mice, simultaneous or prior application of unlabeled gentamicin (10 mg/kg) diminished the renal concentration of 3H-gentamicin, and aprotinin (10 mg/kg) was able to compete with labeled aprotinin. Aprotinin did not diminish the renal accumulation of gentamicin and vice versa. However, since 10 mg/kg aprotinin raised also the plasma concentrations of both 3H-gentamicin and 125I-aprotinin, the evidences resulting from these experiments are limited. Mouse kidney cortex was processed for light and electron microscopic autoradiography at different times following i.v. injection of 3H-gentamicin. Gentamicin enters the apical part of proximal tubule cells. Initially, brush border and basement membrane labeling is prominent, whereas lysosomes appear as intense and prevalent stores 20 min or later after injection. Fractionation of 3H-gentamicin loaded kidneys showed a similar distribution pattern of radioactivity and the lysosomal marker β-galactosidase. The same was true when the crude lysosomal fraction was subjected to density gradient centrifugation, which corroborates the microscopical findings. Radioactivity is partially bound to lysosomal structures, for repeated freezing of loaded lysosomes left 35% of radioactivity particle-bound. It is concluded that both gentamicin and peptides are handled in a similar manner by adsorption, followed by endocytosis and lysosomal sequestration in proximal tubule cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00505080
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  • 3
    Electronic Resource
    Electronic Resource
    Blockade by tetanus and botulinum A toxin of postganglionic cholinergic nerve endings in the myenteric plexus (1980)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 312 (1980), S. 255-263 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00499155
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  • 4
    Electronic Resource
    Electronic Resource
    Palytoxin binds to and inhibits kidney and erythrocyte Na+, K+-ATPase (1984)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 325 (1984), S. 85-87 
    Details
    ISSN: 1432-1912
    Keywords: Na+, K+-ATPase ; Palytoxin ; Ouabain ; Kidney ; Erythrocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Hog kidney Na+, K+-ATPase, purified to the microsomal stage and activated with detergent, binds palytoxin, as shown by the nearly complete competition of the toxin with 3H-ouabain. The K i-values of palytoxin, but not of ouabain, depend on the protein concentration; this indicates additional binding sites for the toxin on kidney membranes. — Palytoxin inhibits the enzymatic activity of the detergent-activated preparation nearly completely (IC50 8·10−7 mol/l). Inhibition of ATPase activity and of ouabain binding are promoted by borate, a known activator of palytoxin. — Palytoxin also inhibits the Na+, K+-ATPase of erythrocyte ghosts in the same dose range. The data are discussed in context with the hypothesis (Chhatwal et al. 1983) that palytoxin raises the cellular permeability by altering the state of Na+, K+-ATPase or its environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00507059
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  • 5
    Electronic Resource
    Electronic Resource
    Tetanus toxin and botulinum a toxin inhibit acetylcholine release from but not calcium uptake into brain tissue (1981)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 316 (1981), S. 143-148 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00505308
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  • 6
    Electronic Resource
    Electronic Resource
    Tetanus toxin blocks the neuromuscular transmission in vitro like botulinum a toxin (1980)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 311 (1980), S. 33-40 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00500299
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