List of abbreviations		 Vocabulary
of micros-
copic
anatomy
specialist terms
explained in
English +
German

Every attempt was made to provide correct information and labelling, however any liability for eventual errors or incompleteness is rejected!
dieser Seite

Editor:
Dr. med.
H. Jastrow
Conditions
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Overview synaptic bodies (SB; Corpuscula synaptica):
Pages with explanations are linked to the text below the images if available
SB of a synapse
in the rat retina		 Sb cut at right angle
human cone		 field of SB overview pineal
gland (guinea pig)		 Field of SB of a pine-
alocyte (guinea-pig)		 SB of a synapse
of an inner hair cell (rat)		 Overview: basal part
of this inner hair cell		 ribbon-like SB of
a pinealocyte (guinea-pig)		 ribbon synapses of the outer
plexiform layer (retina, rat)		 Ribbon synapses of
a human rod & a cone
Animations of reconstructed SBs of pinealocytes (Click the images to start the animations !)
1: group of plate-like SBs
(guinea-pig pineal gland)		 2: shield-like SBs after constant light exposure
(guinea-pig pineal gland)		 3: lump-like SBs caused by constant light
(guinea-pig pineal gland)		 4: stereo animations of a field of SBs present in a pinealocyte of a Sprague-Dawley rat
Localisations of synaptic bodies (synaptic ribbons) in the human retina
rod terminals, outer
plexiform layer		 rod terminal
(4 h post mortem)		 cone & rod terminals
serial image 1		 cone & rod terminals
serial image 2		 cone & rod terminals
serial image 3		 ribbon synapses
rods & cone		 cone terminal with multiple 
SBs, outer plexiform layer		 rod bipolar cell, inner nuclear layer
ectopic synaptic ribbon
Animations of reconstructed SBs of cells of the human retina (Click the images to start the animations !)
5: 1 cone & 4 rod ribbon synapses
+ postsynaptic cell processes		 6: stereo animation of a rod ribbon synapse
(outer plexiform layer)		 7: ribbon synapses and postsynaptic processes of a cone
(outer plexiform layer)		 8: synaptic bodies (ribbons and plates) in
axons of bipolar cells (inner plexiform layer) 
Synaptic bodies (SB; Terminologia histologica: Corpuscula synaptica) consist of an electron-dense proteinaceous structure that is surrounded by synaptic vesicles. In most cases SBs appear as synaptic ribbons (Terminologia histologica: Fasciolus synapticus). They are located close to the cell membrane or attached to the latter close to the active zone where neurotransmitter is released, i.e. they are presynaptic.
SB are encountered in synapses with a high vesicle turnover: photoreceptor cells (rods and cones) and bipolar cells of the retina, cochlear receptor cells of the inner ear (inner and outer hair cells; here often spheres or irregular lump-like structures), receptor cells of the vestibular organs (Macula sacculi and utriculi as well as the Crista ampullaris: bottle-like hair cells [type 1 cells] and cylindrical hair cells [type 2 cells]), celles of the paratympanic organ and pinealocytes, the parenchymal cells of the pineal gland.
SB bind glutamate-containing neurotransmitter vesicles via fine proteinaceous "arms". They change in morphology and size depending on light conditions and stimuli and constitute a reservoir of synaptic vesicles. Some autors assume that they transport synaptic vesicles to the cell membrane.
Three dimensional reconstruction of these organells revealed that most of them have a plate- or band-like shape in the pineal gland (animations 1,4) or human retina (animations 5-8). These ribbons / plates have a constant thickness of 30 to 40 nm. Apart from single SBs, fields of over 20 somewhat parallel ordered structures occur. Under constant light strange shield-like (animation 2), spherical or irregular lump-like structures (animation 3) are seen. In the dark-adapted retina of many animals most SBs are C- to horesshoe-like structures whereas in humans they mostly appear as ribbons. They are presynaptically anchored to an electron-dense material that appears in sections of rod synapses as an arciform density. Rod SBs mostly are bent plates, in cones band-like structures predominate. Therefore the term synaptic ribbons has been established in literature. Protrusions on SBs are seen under light conditions, further spherical SBs (synaptic spheres) with no relation to the cell membrane appear. Constant light leads to remarkable changes of SBs not only in the retina but also in the pineal gland as demonstrated in animations 2 and 3.

--> Presentation of 3D-reconstructions of SBs in the retina, 2 (human retina)
--> retina, pineal gland, synapse, vesicles, nerve tissue
--> Electron microscopic atlas Overview
--> Homepage of the workshop

Page, images & copyright H. Jastrow.