Perspectives in neuroscience: The meaning of a mini

• Published in: Science (American Association for the Advancement of Science) Vol. 293; no. 5529; pp. 443 - 444
• Main Authors: Verstreken, P, Bellen, HJ
• Format: Journal Article
• Language: English
• Published: 20.07.2001
• ISSN: 0036-8075

Nerve cells communicate with one another by releasing neurotransmitter molecules at specialized junctions between neurons called synapses. In response to electrical impulses (action potentials) transmitted along the nerve axon, synaptic vesicles fuse with the neuron's presynaptic membrane, releasing their neurotransmitter contents into the synaptic cleft. The neurotransmitter then diffuses across the synaptic cleft, activating receptors in the postsynaptic membrane. Usually, synaptic vesicles fuse with the presynaptic membrane in response to action potentials, but spontaneous fusion resulting in the release of a single vesicle's contents has been recorded in the absence of action potentials. When a single synaptic vesicle spontaneously fuses with the presynaptic membrane, neurotransmitter diffuses across the synaptic cleft and activates postsynaptic receptors, eliciting a miniature endplate potential or mini. Spontaneous fusion usurps some (but not all) of the molecular machinery required for action potential-dependent fusion. Indeed, genetic manipulation or toxin treatment that blocks neurotransmitter release evoked by action potentials also blocks spontaneous fusion.