Retina bipolar cell
Retinal bipolar cell | |
---|---|
horizontal cells | |
Postsynaptic connections | Retinal ganglion cells and amacrine cells |
Identifiers | |
MeSH | D051245 |
NeuroLex ID | nifext_31 |
Anatomical terms of neuroanatomy] |
As a part of the
. They act, directly or indirectly, to transmit signals from the photoreceptors to the ganglion cells.Structure
Function
Bipolar cells receive synaptic input from either rods or cones, or both rods and cones, though they are generally designated rod bipolar or cone bipolar cells. There are roughly 10 distinct forms of cone bipolar cells, however, only one rod bipolar cell, due to the rod receptor arriving later in the evolutionary history than the cone receptor[attribution needed].
In the dark, a photoreceptor (rod/cone) cell will release glutamate, which inhibits (hyperpolarizes) the ON bipolar cells and excites (depolarizes) the OFF bipolar cells. In light, however, light strikes the photoreceptor cell which causes it to be inhibited (hyperpolarized) due to the activation of opsins which activate G-Proteins that activate phosphodiesterase (PDE) which cleaves cGMP into 5'-GMP. In photoreceptor cells, there is an abundance of cGMP in dark conditions, keeping cGMP-gated Na channels open and so, activating PDE diminishes the supply of cGMP, reducing the number of open Na channels and thus hyperpolarizing the photoreceptor cell, causing less glutamate to be released. This causes the ON bipolar cell to lose its inhibition and become active (depolarized), while the OFF bipolar cell loses its excitation (becomes hyperpolarized) and becomes silent.[1]
Rod bipolar cells do not synapse directly on to ganglion cells. Instead, rod bipolar cells synapse on to a
OFF bipolar cells synapse in the outer layer of the inner plexiform layer of the retina, and ON bipolar cells terminate in the inner layer of the inner plexiform layer.
Signal transmission
Bipolar cells effectively transfer information from rods and cones to ganglion cells. The horizontal cells and the amacrine cells complicate matters somewhat. The horizontal cells introduce
The mechanism for producing the center of a bipolar cell's
See also
Notes
- ISBN 978-0-87893-694-6.
- S2CID 43225212.
- PMID 23690563.
References
- Nicholls, John G.; A. Robert Martin; Bruce G. Wallace; Paul A. Fuchs (2001). From Neuron to Brain. Sunderland, Mass: Sinauer Associates. ISBN 0-87893-439-1.
- Masland RH (2001). "The fundamental plan of the retina". Nat. Neurosci. 4 (9): 877–86. S2CID 205429773.
External links
- Retinal+bipolar+cells at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
- Diagram at mcgill.ca
- NIF Search - Retinal Bipolar Cell via the Neuroscience Information Framework