Nicotinic acetylcholine receptors regulate clustering, fusion and acidification of the rat brain synaptic vesicles

Autor: Irene O. Trikash, Ludmila Kasatkina, Olena Lykhmus, Maryna Skok
Rok vydání: 2020
Předmět:
Male
0301 basic medicine
Synaptic vesicle clustering
AO
acridine orange
alpha7 Nicotinic Acetylcholine Receptor
Nicotinic acetylcholine receptor
Synaptic cleft
levetiracetam
membrane fusion
synaptic vesicle clustering
Nicotinic Antagonists
Synaptic vesicle
Article
SVs
synaptic vesicles
Mice
03 medical and health sciences
Cellular and Molecular Neuroscience
chemistry.chemical_compound
0302 clinical medicine
synaptic vesicles
R18
octadecyl rhodamine B
Animals
Nicotinic Agonists
Rats
Wistar
Neurotransmitter
Acetylcholine receptor
SV2A
Mice
Knockout
Lev
levetiracetam
Cell Membrane
Brain
Cell Biology
Hydrogen-Ion Concentration
nAChR
nicotinic acetylcholine receptor
Rats
Cell biology
Mice
Inbred C57BL
030104 developmental biology
Nicotinic agonist
SV2A
synaptic vesicle glycoprotein 2A
chemistry
PM
plasma membrane
Female
030217 neurology & neurosurgery
Zdroj: Neurochemistry International
ISSN: 0197-0186
DOI: 10.1016/j.neuint.2020.104779
Popis: The brain nicotinic acetylcholine receptors (nAChRs) expressed in pre-synaptic nerve terminals regulate neurotransmitter release. However, there is no evidence for the expression of nAChRs in synaptic vesicles, which deliver neurotransmitter to synaptic cleft. The aim of this paper was to investigate the presence of nAChRs in synaptic vesicles purified from the rat brain and to study their possible involvement in vesicles life cycle. According to dynamic light scattering analysis, the antibody against extracellular domain (1-208) of α7 nAChR subunit inhibited synaptic vesicles clustering. Sandwich ELISA with nAChR subunit-specific antibodies demonstrated the presence of α4β2, α7 and α7β2nAChR subtypes in synaptic vesicles and showed that α7 and β2 nAChR subunits are co-localized with synaptic vesicle glycoprotein 2A (SV2A). Pre-incubation with either α7-selective agonist PNU282987 or nicotine did not affect synaptic vesicles clustering but delayed their Ca2+-dependent fusion with the plasma membranes. In contrast, nicotine but not PNU282987 stimulated acidification of isolated synaptic vesicles, indicating that α4β2 but not α7-containing nAChRs are involved in regulation of proton influx and neurotransmitter refilling. Treatment of rats with levetiracetam, a specific modulator of SV2A, increased the content of α7 nAChRs in synaptic vesicles accompanied by increased clustering but decreased Ca2+-dependent fusion. These data for the first time demonstrate the presence of nAChRs in synaptic vesicles and suggest an active involvement of cholinergic regulation in neurotransmitter release. Synaptic vesicles may be an additional target of nicotine inhaled upon smoking and of α7-specific drugs widely discussed as anti-inflammatory and pro-cognitive tools.
Highlights 1. The α4β2 and α7 nAChRs are present in rat brain synaptic vesicles close to SV2A protein. 2. The α7(1-208)-specific antibody inhibits synaptic vesicles clustering. 3. Activation of either α4β2 or α7 nAChRs delays synaptic vesicles fusion with plasma membranes. 4. Activating α4β2 nAChRs stimulates the proton influx in synaptic vesicles. 5. Levetiracetam up-regulates α7 nAChRs in synaptic vesicles, favors clustering but decreases fusion.
Databáze: OpenAIRE
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