Biomaterial Database

Quantitative synaptology of the inner plexiform layer of the retina of Bufo marinus. 1994

R Gábriel, and M Wilhelm

Department of Zoology, Janus Pannonius University, Pécs, Hungary.

We have performed a quantitative electron microscope study on the inner plexiform layer (IPL) of Bufo marinus retina in order to reveal the types, morphological features, densities and distributions of synapses and compare these parameters to samples derived from the visual streak area and the retinal periphery. The IPL has been subdivided into five sublayers (SLs) and the data were analysed accordingly. The density of synapses was found to be about 140.000/mm2 and was not significantly different between the central and peripheral retina. In both locations, SL3 contained the smallest number of synapses. The amacrine:bipolar presynaptic profile ratio was about 7, both in the centre and at the periphery. Amacrine-amacrine interactions greatly outnumbered other types of synapses and occurred most frequently in SL2 and 4. Bipolar cell outputs are directed mostly to amacrine-amacrine dyads, and the inputs to bipolar terminals from amacrine cells somewhat outnumber those of the outputs. The largest number of synapses directed to ganglion cells was observed in SL1 and derived from amacrine cells. The correlation between the stratification of neurochemically and morphologically characterised amacrine cells, and the morphologically and physiologically characterised ganglion cell types in the IPL are discussed.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
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
D002024	Bufo marinus	A species of the true toads, Bufonidae, becoming fairly common in the southern United States and almost pantropical. The secretions from the skin glands of this species are very toxic to animals.	Rhinella marina,Toad, Giant,Toad, Marine,Giant Toad,Giant Toads,Marine Toad,Marine Toads,Toads, Giant,Toads, Marine
D002452	Cell Count	The number of CELLS of a specific kind, usually measured per unit volume or area of sample.	Cell Density,Cell Number,Cell Counts,Cell Densities,Cell Numbers,Count, Cell,Counts, Cell,Densities, Cell,Density, Cell,Number, Cell,Numbers, Cell
D005260	Female		Females
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
D012165	Retinal Ganglion Cells	Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.	Cell, Retinal Ganglion,Cells, Retinal Ganglion,Ganglion Cell, Retinal,Ganglion Cells, Retinal,Retinal Ganglion Cell
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
D048429	Cell Size	The quantity of volume or surface area of CELLS.	Cell Volume,Cell Sizes,Cell Volumes,Size, Cell,Sizes, Cell,Volume, Cell,Volumes, Cell