Biomaterial Database

[Effects of prolonged darkness and background illumination on cone horizontal cells in carp retina: a correlative study of morphology and physiology]. 1992

J Zhang, and X E Song, and H H Wang, and X L Yang

Shanghai Institute of Physiology, Academia Sinica.

Using intact, immobilized carp preparations, changes in light responsiveness of cone horizontal cells and ultrastructures of their terminals in cone pedicles (HCTs) were correlatively examined in prolonged (greater than 2 h) darkness and after the presentation of a dim background light. Following background illumination cone horizontal cells exhibit high light responsiveness and HCTs give rise to a lot of long, fingerlike or ball-like extensions, called slender or round spinules. When the retina is left in the dark for more than 2 h, the light responsiveness of these cells is depressed, which is accompanied by a dramatic decrease of spinules. Thus light responsiveness of the cone horizontal cells seems to be well correlated with the number of spinules. The results suggest that spinules may play an important role in regulating light responsiveness of cone horizontal cells following background illumination by altering the efficacy of signal transfer across the synapses between cone photoreceptors and cone horizontal cells.

UI	MeSH Term	Description	Entries
D008029	Lighting	The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.	Illumination
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D010786	Photoreceptor Cells	Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.	Ciliary Photoreceptor Cells,Ciliary Photoreceptors,Rhabdomeric Photoreceptor Cells,Rhabdomeric Photoreceptors,Cell, Ciliary Photoreceptor,Cell, Photoreceptor,Cell, Rhabdomeric Photoreceptor,Cells, Ciliary Photoreceptor,Cells, Photoreceptor,Cells, Rhabdomeric Photoreceptor,Ciliary Photoreceptor,Ciliary Photoreceptor Cell,Photoreceptor Cell,Photoreceptor Cell, Ciliary,Photoreceptor Cell, Rhabdomeric,Photoreceptor Cells, Ciliary,Photoreceptor Cells, Rhabdomeric,Photoreceptor, Ciliary,Photoreceptor, Rhabdomeric,Photoreceptors, Ciliary,Photoreceptors, Rhabdomeric,Rhabdomeric Photoreceptor,Rhabdomeric Photoreceptor Cell
D012160	Retina	The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.	Ora Serrata
D002347	Carps	Common name for a number of different species of fish in the family Cyprinidae. This includes, among others, the common carp, crucian carp, grass carp, and silver carp.	Carassius carassius,Crucian Carp,Cyprinus,Grass Carp,Carp,Ctenopharyngodon idellus,Cyprinus carpio,Hypophthalmichthys molitrix,Koi Carp,Silver Carp,Carp, Crucian,Carp, Grass,Carp, Koi,Carp, Silver,Carps, Crucian,Carps, Grass,Carps, Silver,Crucian Carps,Grass Carps,Silver Carps
D003623	Dark Adaptation	Adjustment of the eyes under conditions of low light. The sensitivity of the eye to light is increased during dark adaptation.	Scotopic Adaptation,Adaptation, Dark,Adaptation, Scotopic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse