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S Lande

Publications and source records attributed to S Lande.

At least 19 recordsLinked to original sources
PubMed1989

Multiple domains of botulinum neurotoxin contribute to its inhibition of transmitter release in Aplysia neurons.

The binding, internalization, and inhibition of transmitter release by botulinum neurotoxin (BoNT) was investigated using the intact toxin, its heavy (HC) or light (LC) chains, and a proteolytic fragment thereof. In Aplysia neurons, blockade of acetylcholine release upon external application of BoNT types A or E was prevented by reducing the temperature to 10 degrees C, due to arresting intoxication at the membrane binding step. At this low temperature, type A HC, H2 (comprised of the N-terminal of HC), or H2L (H2 disulfide-linked to LC) antagonized the neuroparalytic action of BoNT A or E, indicating that the latter bind saturably to common ecto-acceptor via the H2 region. In contrast, H2L was unable to counteract BoNT-induced paralysis at the murine neuromuscular junction. In accordance with this species difference, unlike native BoNT, saturable binding of 125I-labeled H2L could not be detected in mammalian peripheral or central nerve terminals. Possibly, more stringent structural requirements form the basis of the toxin's greater effectiveness in inhibiting neurotransmission at mouse nerve muscle synapses than Aplysia nerve terminals. In further identification of functional domains in the toxin, an unprocessed single-chain form of BoNT type E was found to be ineffective when applied extra- or intracellularly to Aplysia neurons. Notably, bath application of the latter to a neuron preinjected with HC, but not H2L or LC, resulted in a blockade of release. This shows that the single-chain species can become internalized and requires, not only LC, but also processed HC for its inhibitory action; consistently, the proteolyzed form of BoNT E was active.

Acetylcholine↗
PubMed1989

Effects of botulinum neurotoxin and Lambert-Eaton myasthenic syndrome IgG at mouse nerve terminals.

The interaction between two presynaptically acting agents, Lambert-Eaton myasthenic syndrome (LEMS) immunoglobulin G (IgG) and purified botulinum neurotoxin (BoNT) type A, was studied. Intracellular microelectrode recordings were carried out on mouse muscles after injection with LEMS IgG. BoNT was either injected before recordings were made or applied in vitro. The time course of the in vitro actions of BoNT on miniature end-plate potential and end-plate potential parameters were not affected by pretreatment with LEMS IgG. After in vivo injection of BoNT, end-plate potential quantal content was reduced to less than 2% of control values, whether or not LEMS IgG had also been previously given. Quantitative electron-microscope autoradiographical analysis showed that neither the binding of 125I-BoNT to acceptors on the nerve terminal membrane nor the pattern of its internalisation were affected by pretreatment with LEMS IgG. We conclude that the effects of BoNT are not affected by LEMS IgG, suggesting different presynaptic binding sites for the two agents.

Action Potentials↗
PubMed1988

High-performance displacement chromatography of melanotropins and their derivatives.

Mixtures containing derivatives of the biological active peptide alpha-melanocyte stimulating hormone (alpha-MSH) or beta-melanocyte stimulating hormone (beta-MSH) were purified by using reversed-phase chromatography in the displacement mode. On a 250 x 4.6 mm octadecyl silica column and with instrumentation used in analytical high-performance liquid chromatography about 30 mg of the peptide mixture were separated by using an aqueous solution of benzyldimethyldodecylamonium bromide as the displacer in a single chromatographic run. The results demonstrate the advantages of displacement over elution in preparative chromatography of peptides on the scale of tens of milligrams that is typical for physiological tissue extracts and in solid-phase peptide synthesis.

Chromatography, High Pressure Liquid↗
PubMed1987

The effects of in vitro application of purified botulinum neurotoxin at mouse motor nerve terminals.

1. Purified botulinum neurotoxin type A (10 nM) was applied in vitro to mouse diaphragm muscles. Intracellular micro-electrode recordings were made continuously in single fibres. 2. This treatment reduced end-plate potential (e.p.p.) amplitudes with a time to half-maximal effect of about 75 min at 22-25 degrees C. E.p.p. rise-times remained fast and unaffected by the toxin. 3. Miniature end-plate potential (m.e.p.p.) frequency was reduced by the toxin to less than 5% of control frequency, and followed a similar time course to the block of e.p.p. amplitudes. The m.e.p.p. rise-time and coefficient of variation (c.v.) of m.e.p.p. amplitude distributions both increased, but the time course of these increases lagged significantly behind the change in frequency. 4. A population of slow rise-time m.e.p.p.s was present in controls at low frequency. This population was found to be unaffected by the toxin. 5. The above-detailed in vitro changes could be explained by the toxin acting by a single common mechanism to inhibit the release process underlying both fast rise-time m.e.p.p.s and e.p.p.s. A distinct release process, which leads to slow rise-time m.e.p.p.s, was unaffected by the toxin.

Action Potentials↗
PubMed1977

A gift of hope.

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Humans↗
PubMed1972

Effect of corticotropin and desglycinamide 9 -lysine vasopressin on suppression of memory by puromycin.

The puromycin-induced blockade of expression of maze learning in mice can be prevented by subcutaneous administration of "Purified Cortrophin Gel" up to 3 days prior to training. A similar protective effect was not found when highly purified corticotropin was tested, but was observed after administration of desglycinamide(9)-lysine vasopressin. It appears that pressorpeptides are more potent protective agents than corticotropin when administered subcutaneously, and that vasopressin contamination of the commercial preparation was probably responsible for the protective effects previously reported. These experiments suggest that vasopressin and its congeners modify memory consolidation in such a way that the "expression" of memory becomes insensitive to puromycin.

Adrenocorticotropic Hormone↗