Chronic blockade of glutamate receptors enhances presynaptic release and downregulates the interaction between synaptophysin-synaptobrevin-vesicle-associated membrane protein 2 - PubMed (original) (raw)

Chronic treatment with glutamatergic blockers upregulates synaptic vesicle recycling. We incubated 15-d-old neurons from control (A–C, G–L) or APV–CNQX-treated (D–F, M–P) cultures for 5 min (A–H, M, and N, histogram in Q) or 25 min (histogram in_Q_) in the presence of Syt-ecto Abs in KRH containing glutamate receptor blockers. In a set of experiments, incubation was performed for 3 min in the presence of 55 m

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KCl (I, L, O, P, histogram in Q). After this incubation, neurons were washed, fixed, detergent-permeabilized, reacted with fluorescein-conjugated goat anti-rabbit IgGs (B, E, G,I, M, O), and counterstained with antibodies against SV2 followed by rhodamine-conjugated goat anti-mouse IgGs (A,D, H, L, N,P). Puncta of immunoreactivity represent presynaptic nerve terminals that outline perikarya and dendrites. Syt-ecto Abs are internalized only at few synaptic contacts in control cultures (B, G) and in most synaptic contacts in APV–CNQX-treated neurons (E, M).C, F, Fluorescein- and rhodamine-merged images. Incubation in the presence of KCl results in Syt-ecto Ab internalization in virtually all synaptic contacts, both in control (I) and treated (O) cultures. Scale bars: A–C, 20.8 μm;D–F, 25 μm; G–P, 3.5 μm.Q, Histogram showing the quantitative evaluation of Syt-ecto-positive synapses in control and in APV–CNQX-treated neurons.