TY - JOUR

T1 - Inhibition of neurotransmitter release in the lamprey reticulospinal synapse by antibody-mediated disruption of SNAP-25 function

AU - Löw, Peter

AU - Norlin, Thomas

AU - Risinger, Carl

AU - Larhammar, Dan

AU - Pieribone, Vincent A.

AU - Shupliakov, Oleg

AU - Brodin, Lennart

PY - 1999/1/1

Y1 - 1999/1/1

N2 - The lamprey giant reticulospinal synapse can be used to manipulate the molecular machinery of synaptic vesicle exocytosis by presynaptic microinjection. Here we test the effect of disrupting the function of the SNARE protein SNAP-25. Polyclonal SNAP-25 antibodies were shown in an in vitro assay to inhibit the binding between syntaxin and SNAP-25. When microinjected presynaptically, these antibodies produced a potent inhibition of the synaptic response. Ba2+ spikes recorded in the presynaptic axon were not altered, indicating that the effect was not due to a reduced presynaptic Ca2+ entry. Electron microscopic analysis showed that synaptic vesicle clusters had a similar organization in synapses of antibody-injected axons as in control axons, and the number of synaptic vesicles in apparent contact with the presynaptic plasma membrane was also similar. Clathrin-coated pits, which normally occur at the plasma membrane around stimulated synapses, were not detected after injection of SNAP-25 antibodies, consistent with a blockade of vesicle cycling. Thus, SNAP-25 antibodies, which disrupt the interaction with syntaxin, inhibit neurotransmitter release without affecting the number of synaptic vesicles at the plasma membrane. These results provide further support to the view that the formation of SNARE complexes is critical for membrane fusion, but not for the targeting of synaptic vesicles to the presynaptic membrane.

AB - The lamprey giant reticulospinal synapse can be used to manipulate the molecular machinery of synaptic vesicle exocytosis by presynaptic microinjection. Here we test the effect of disrupting the function of the SNARE protein SNAP-25. Polyclonal SNAP-25 antibodies were shown in an in vitro assay to inhibit the binding between syntaxin and SNAP-25. When microinjected presynaptically, these antibodies produced a potent inhibition of the synaptic response. Ba2+ spikes recorded in the presynaptic axon were not altered, indicating that the effect was not due to a reduced presynaptic Ca2+ entry. Electron microscopic analysis showed that synaptic vesicle clusters had a similar organization in synapses of antibody-injected axons as in control axons, and the number of synaptic vesicles in apparent contact with the presynaptic plasma membrane was also similar. Clathrin-coated pits, which normally occur at the plasma membrane around stimulated synapses, were not detected after injection of SNAP-25 antibodies, consistent with a blockade of vesicle cycling. Thus, SNAP-25 antibodies, which disrupt the interaction with syntaxin, inhibit neurotransmitter release without affecting the number of synaptic vesicles at the plasma membrane. These results provide further support to the view that the formation of SNARE complexes is critical for membrane fusion, but not for the targeting of synaptic vesicles to the presynaptic membrane.

KW - Exocytosis

KW - SNARE

KW - Synaptic vesicle

KW - Synaptobrevin

KW - Syntaxin

UR - http://www.scopus.com/inward/record.url?scp=0344577857&partnerID=8YFLogxK

U2 - 10.1016/S0171-9335(99)80029-6

DO - 10.1016/S0171-9335(99)80029-6

M3 - Article

C2 - 10604655

AN - SCOPUS:0344577857

VL - 78

SP - 787

EP - 793

JO - European Journal of Cell Biology

JF - European Journal of Cell Biology

SN - 0171-9335

IS - 11

ER -