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Unformatted text preview: and the neuron that responds to the NT is postsynaptic . Neurotransmitter Release When an AP arrives at the axon terminal, the depolarization of the membrane causes the opening of VG-Ca 2+ channels. Ca 2+ diffuses into cell through the open channels at the terminal and causes the synaptic vesicles to "fuse " with the plasma membrane. This fusion releases the contents of the synaptic vesicle and the NTs enter the synaptic cleft and diffuse away from the site of release. If the neurotransmitters bind to receptors on the target, the receptors change shape and initiate a response in the postsynaptic cell. The response of the target can vary based upon the receptor type and what the target is designed to do. Neuronal targets generally exhibit a local potential, which can be either excitatory or inhibitory . If the presynaptic neuron is innervating a gland, the gland will secrete while muscular targets will contract....
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- Fall '10