[3H]-noradrenaline secretion from rat cortex synaptosomes perforated with Staphylococcus aureus alpha-toxin

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Synaptosomes are crucial for studying neurotransmitter release.
• Existing methods for synaptosome permeabilization have limitations.
• Understanding regulated exocytosis requires accessible intracellular environments.

Purpose of the Study:

• To establish a novel method for perforating rat cortex synaptosomes using Staphylococcus aureus alpha-toxin.
• To characterize the properties of alpha-toxin-perforated synaptosomes for studying neurotransmitter release.
• To assess the utility of this preparation for investigating regulated exocytosis.

Main Methods:

• Perforation of rat cortex synaptosomes with high concentrations of Staphylococcus aureus alpha-toxin.
• Measurement of [3H]-noradrenaline release and dependence on Ca2+ and MgATP.
• Assessment of lactate dehydrogenase efflux and antibody entry to evaluate membrane integrity.
• Comparison of Ca2+-dependent release characteristics with other permeabilization methods.

Main Results:

• High concentrations of alpha-toxin effectively perforated synaptosomes without compromising cell integrity.
• Ca2+-dependent [3H]-noradrenaline release showed similarities to other cell models and was largely independent of omega-conotoxin GVIA.
• MgATP dependence of release increased over time, indicating a role in sustained exocytosis.
• Alpha-toxin-perforated synaptosomes exhibited greater resistance to rundown compared to streptolysin-O-perforated synaptosomes.

Conclusions:

• Staphylococcus aureus alpha-toxin provides a reliable method for perforating rat cortex synaptosomes.
• This preparation is suitable for studying Ca2+-dependent neurotransmitter release and regulated exocytosis.
• The alpha-toxin method offers advantages in stability and utility for neurobiology research.