Adrenal medullary chromaffin cells in vitro

“…Chromaffin cells were dissociated by protease digestion of bovine adrenal glands [40] and incubated as monolayer cultures at 1 X lo6 cells/well on 24-well tissue-culture plates in Dulbecco's modified Eagle's medium supplemented with 10% foetal calf serum, 2 mM glutamine, 2 mM sodium pyruvate, 50 pg/ml gentamycin, 10 pM cytosinearabinofurano- [42]. At the end of every experiment, the cells in each well were solubilised with Triton X-100 in order to gain a representative measure of the total amount of catecholamine remaining.…”

Section: Methodsmentioning

confidence: 99%

Botulinum A and the light chain of tetanus toxins inhibit distinct stages of Mg · ATP‐dependent catecholamine exocytosis from permeabilised chromaffin cells

Lawrence

Weller

Dolly

1994

European Journal of Biochemistry

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Susceptibilities of Mg . ATP-independent and Mg . ATP-requiring components of catecholamine secretion from digitonin-permeabilised chromaffin cells to inhibition by Clostridial botulinum type A and tetanus toxins were investigated. These toxins are Zn2+-dependent proteases which specifically cleave the 25-kDa synaptosomal-associated protein (SNAP-25) and vesicle-associated membrane protein (VAMP) 11, respectively. When applied to permeabilised chromaffin cells they rapidly inhibited secretion in the presence of Mg . ATP but the catecholamine released in the absence of Mg . ATP, thought to represent fusion of primed granules, was not perturbed. The toxins can exert their effects per se in the absence of the nucleotide complex; therefore, Mg . ATP-requiring steps of secretion are implicated as roles for their targets. Primed release was lost rapidly after permeabilisation of the cells but could be maintained by including Mg . ATP during the incubation before stimulating release with Ca". This ability of Mg . ATP to maintain primed release was only partially inhibited by botulinum neurotoxin A whereas it was abolished by tetanus toxin, consistent with the distinct substrates for these toxins. This study reveals a component of release within which these proteins are either resistant to cleavage by these toxins or in such a position that degradation can no longer prevent granule fusion. Differences in the steps of release at which these toxins can affect inhibition are also revealed.Digitonin-permeabilised chromaffin cells provide an excellent model for determining the molecular requirements of exocytosis. The detergent-induced pores allow rapid entry and exit of molecules of up to at least 150 kDa whilst the cells retain a good secretory response to a Ca" stimulus [l, 21. This has allowed studies of the effects on exocytosis of cytosolic constituents leaving the cell, including re-addition of leaked cytosolic proteins in a purified and concentrated form [3]. In this way previous workers have demonstrated an involvement in exocytosis of Mg2+, ATP [4, 51 and GTP [6, 71 together Investigations into the mechanism of the secretory process have been greatly helped by the use of specific inhibitors of exocytosis, particularly botulinum (BoNT) and tetanus (TeTx) neurotoxins, produced by members of the Clostridium botulinum family (types A-G) and the closely related Clostridium tetani, respectively. These proteins consist of a heavy (HC, =100kDa) and a light (LC, =50kDa) chain linked by a disulphide bond [13]. Both toxins bind via their HC to distinct acceptors on nerve terminals [14-161 and

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“…Chromaffin cells from bovine adrenal medulla were prepared as described [9]. Briefly, fresh adrenals were dissected free of fat and connective tissue and immediately rinsed free of blood by several retrograde injections of ice-cold buffer I (mM: 150 NaCl, 5 KCI, 10 glucose, 10 Hepes, pH 7.4, supplemented with 50 IU penicillin, 50 pg/ml streptomycin and 0.25 pg/ml fungizone).…”

Section: Cell Culturesmentioning

confidence: 99%

Reductive chain separation of botulinum A toxin — a prerequisite to its inhibitory action on exocytosis in chromaffin cells

1989

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Cleavage of the disulfide bond linking the heavy and the light chains of tetanus toxin is necessary for its inhibitory action on exocytotic release of catecholamines from permeabilized chromaffin cells [(1989) FEBS Lett. 242, 245-248; J. Neurochem., in press]. The related botulinum A toxin also consists of a heavy and a light chain linked by a disulfide bond. The actions of both neurotoxins on exocytosis were presently compared using streptolysin 0-permeabilized bovine adrenal chromaffin cells. Botulinum A toxin inhibited Ca*+-stimulated catecholamine release from these cells. Addition of dithiothreitol lowered the effective doses to values below 5 nM. Under the same conditions, the effective doses of tetanus toxin were decreased by a factor of five. This indicates that the interchain S-S bond of botulinum A toxin must also be split before the neurotoxin can exert its effect on exocytosis.

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Adrenal medullary chromaffin cells in vitro

Cited by 317 publications

References 0 publications

Inhibition of nicotinic receptor‐mediated responses in bovine chromaffin cells by diltiazem

Inhibition of nicotinic receptor‐mediated responses in bovine chromaffin cells by diltiazem

Botulinum A and the light chain of tetanus toxins inhibit distinct stages of Mg · ATP‐dependent catecholamine exocytosis from permeabilised chromaffin cells

Reductive chain separation of botulinum A toxin — a prerequisite to its inhibitory action on exocytosis in chromaffin cells

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