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Neurons communicate with each other and with other cells at synapses. In electrical synapses, which are common among invertebrates, the AP spreads directly from presynaptic to postsynaptic cell. The most common type of synapse in the vertebrate nervous system is the chemical synapse, in which neurotransmitters released from a presynaptic cell induce changes in a membrane potential of a postsynaptic cell. This section begins with a discussion of the synapses between neurons and muscle cells. We then consider the diversity in synapses between neurons and how they integrate information.
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Action potentials arriving at a chemical synapse such as the neuromuscular junction trigger an influx of Ca2+ that activates the molecular machinery responsible for vesicular release of neurotransmitter.
Gap junctions are comprised of connexins connecting electrically-
The action of a neurotransmitter depends on the nature of the postsynaptic receptor.
Neurotransmitter action can be terminated by diffusion, reuptake, or degradation.
Agonists and antagonists are drugs that target specific receptors.