Receptor potential

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Receptor potential, a type of graded potential, is the transmembrane potential difference of a sensory receptor.

A receptor potential is often produced by sensory transduction. It is generally a depolarizing event resulting from inward current flow. The influx of current will often bring the membrane potential of the sensory receptor towards the threshold for triggering an action potential.

A receptor potential is a form of graded potential, as is a generator potential. It arises when the receptors of a stimulus are separate cells. An example of this is in a taste bud, where taste is converted into an electrical signal sent to the brain. When stimulated the taste bud triggers the release of neurotransmitter through exocytosis of synaptic vesicles from the presynaptic membrane. The neurotransmitter molecules diffuse across the synaptic cleft to the postsynaptic membrane. A postsynaptic potential is then produced in the first order neurone, and if the stimulus is strong enough to reach threshold this may generate an action potential which may propagate along the axon into the central nervous system.