scholarly journals Isolation of pure cholinergic nerve endings from the electric organ of Torpedo marmorata

1976 ◽  
Vol 160 (1) ◽  
pp. 113-115 ◽  
Author(s):  
M Israël ◽  
R Manaranche ◽  
P Mastour-Frachon ◽  
N Morel
Keyword(s):  
Rapid Method ◽  
Electric Organ ◽  
Nerve Endings ◽  
Torpedo Marmorata ◽  
Cholinergic Nerve

A rapid method for the preparation of highly purified cholinergic nerve endings from the electric organ of Torpedo is described. The endings retain their cytoplasmic components, as shown by biochemical and morphological observations. The homogeneity of these synaptosomes make them a useful tool for further studies.

scholarly journals Biosynthesis of acetyl-coenzyme A in the electric organ of Torpedo marmorata in relation to acetylcholine metabolism

1977 ◽  
Vol 166 (3) ◽  
pp. 447-453 ◽  
Author(s):  
M F Diebler ◽  
Y Morot-Gaudry
Keyword(s):  
Choline Acetyltransferase ◽  
Gel Filtration ◽  
Electric Organ ◽  
Nerve Endings ◽  
Tissue Extract ◽  
Torpedo Marmorata ◽  
Forward Reaction ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Acetylcholine Metabolism

Formation of acetyl-CoA through acetyl-CoA synthetase (forward reaction) and through choline acyltransferase (backward reaction) was investigated in tissue extract from the electric organ of Torpedo marmorata. When the tissue extract was submitted to gel filtration on Sephadex G-25, the formation of acetyl-CoA by acetyl-CoA synthetase appeared fully dependent on ATP and CoA and partially dependent on acetate (an endogenous supply of acetate is discussed). Choline acetyltransferase was a potent source of acetyl-CoA, only requiring acetylcholine and CoA, and was much more efficient than acetyl-CoA synthetase for concentrations of acetylcholine likely to be present in nerve endings.

scholarly journals THE FINE STRUCTURE OF THE ELECTRIC ORGAN OF TORPEDO MARMORATA

1965 ◽  
Vol 24 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Michael N. Sheridan
Keyword(s):  
Fine Structure ◽  
Connective Tissue ◽  
Basement Membrane ◽  
Intercellular Space ◽  
Electric Organ ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Nerve Fibers ◽  
Nerve Endings ◽  
Torpedo Marmorata

The fine structure of the electric organ of the fish Torpedo marmorata has been examined after osmium tetroxide or potassium permanganate fixation, acetone dehydration, and Araldite embedment. This organ consists of stacks of electroplaques which possess a dorsal noninnervated and a ventral richly innervated surface. Both surfaces are covered with a thin basement membrane. A tubular membranous network whose lumen is continuous with the extracellular space occupies the dorsal third of the electroplaque. Nerve endings, separated from the ventral surface of the electroplaque by a thin basement membrane, contain synaptic vesicles (diameter 300 to 1200 A), mitochondria, and electron-opaque granules (diameter 300 A). Projections from the nerve endings occupy the lumina of the finger-like invaginations of the ventral surface. The cytoplasm of the electroplaques contains the usual organelles. A "cellular cuff" surrounds most of the nerve fibers in the intercellular space, and is separated from the nerve fibre and its Schwann cell by a space containing connective tissue fibrils. The connective tissue fibrils and fibroblasts in the intercellular space are primarily associated with the dorsal surface of the electroplaque.

scholarly journals Isolation of pure cholinergic nerve endings from Torpedo electric organ. Evaluation of their metabolic properties.

1977 ◽  
Vol 75 (1) ◽  
pp. 43-55 ◽  
Author(s):  
N Morel ◽  
M Israel ◽  
R Manaranche ◽  
P Mastour-Frachon
Keyword(s):  
Synaptic Vesicles ◽  
Morphological Analysis ◽  
Electric Organ ◽  
Nerve Endings ◽  
Cholinergic Nerve ◽  
Membrane Attachment ◽  
Biochemical Measurements ◽  
Torpedo Electric Organ ◽  
Metabolic Properties

Pure cholinergic nerve endings (synaptosomes) were isolated from the electric organ of Torpedo by a rapid procedure. These synaptosomes are approximately 3 micron in diameter. They contain an occasional mitochondrion, numerous synaptic vesicles, and sometimes an active zone is observed. No postynaptic membrane attachment is found. This nerve ending fraction is extremely pure as shown by morphological controls and biochemical data. It is rich in choline acetyltransferase (450 nmol/h per mg protein) and acetylcholine (ACh) (130 nmol/mg protein). The isolated endings retain their cytoplasmic components and they synthesize ACh and are stable in vitro for several hours, as shown by biochemical measurements and morphological analysis.

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