The Effect of Neurotransmitter Release upon Phospholipid Composition and Fatty Acid Turnover in Synaptic Vesicles of Torpedo marmorata Electric Organ and Guinea-Pig Cerebral Cortex

1975 ◽  
Vol 3 (2) ◽  
pp. 263-265 ◽  
Author(s):  
R. ROY BAKER ◽  
MICHAEL J. DOWDALL ◽  
VICTOR P. WHITTAKER
Keyword(s):  
Cerebral Cortex ◽  
Fatty Acid ◽  
Guinea Pig ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Phospholipid Composition ◽  
Electric Organ ◽  
Torpedo Marmorata ◽  
Fatty Acid Turnover

scholarly journals Stimulation of the production of unesterified fatty acids in nerve endings of guinea-pig brain in vitro by noradrenaline and 5-hydroxytryptamine

1972 ◽  
Vol 126 (3) ◽  
pp. 575-585 ◽  
Author(s):  
C. J. Price ◽  
C. E. Rowe
Keyword(s):  
Fatty Acids ◽  
Cerebral Cortex ◽  
Guinea Pig ◽  
Synaptic Vesicles ◽  
Nerve Endings ◽  
Synaptic Membranes ◽  
Pig Brain ◽  
Guinea Pig Brain ◽  
Stimulation Of

1. Noradrenaline (1mm) and 5-hydroxytryptamine (1mm) stimulated the production of unesterified palmitate, oleate, stearate and arachidonate in nerve endings (synaptosomes) isolated from combined guinea-pig cerebral cortex and cerebellum. 2. Iproniazid phosphate (0.36mm) increased the concentrations of the same acids in osmotically ruptured synaptosomes. Further addition of 1mm-noradrenaline or 1mm-5-hydroxytryptamine reversed this increase. 3. Noradrenaline (0.01mm) stimulated the production of unesterified fatty acids in isolated synaptic membranes. 5-Hydroxytryptamine (0.01mm) stimulated the production of unesterified fatty acids in synaptic membranes and synaptic vesicles.

scholarly journals Electrokinetic properties of isolated cerebral-cortex synaptic vesicles

1973 ◽  
Vol 136 (4) ◽  
pp. 919-926 ◽  
Author(s):  
Jack McLaughlin ◽  
Kenneth R. Case ◽  
H. Bruce Bosmann
Keyword(s):  
Cerebral Cortex ◽  
Sialic Acid ◽  
Ionic Strength ◽  
Guinea Pig ◽  
Concanavalin A ◽  
Synaptic Vesicles ◽  
Carboxyl Groups ◽  
Electrokinetic Properties ◽  
Ph Dependent ◽  
Vesicle Mobility

Synaptic vesicles isolated from guinea-pig cerebral cortex had an electrophoretic mobility of −3.55μm·s-1·V-1·cm in saline–sorbitol, pH7.2, at 25°C (ionic strength 0.015g-ions/1). The mobility was pH-dependent, varied with ionic strength and indicated that the vesicular surface contained weak acidic functions with a pKa in the range 3.0–3.8. Although the vesicular surface was determined to be highly negatively charged, treatment with neuraminidase had no effect on mobility and indicated that the relatively strong carboxyl groups of sialic acid do not contribute significantly to vesicular electrokinetic properties. Treatment of synaptic vesicles with trypsin or trypsinized concanavalin A resulted in increases in mobility, but treatment with ribonuclease, deoxyribonuclease, chrondroitinase ABC or hyaluronidase had no significant effect on mobility. Mn2+or Ca2+was more effective in decreasing vesicle mobility than was Mg2+, Sr2+or Ba2+. The electrokinetic properties of the synaptic vesicle surface are discussed and contrasted with the properties of the synaptosomal membrane.

scholarly journals Phospholipid turnover in Torpedo marmorata electric organ during discharge in vivo

1976 ◽  
Vol 158 (3) ◽  
pp. 557-565 ◽  
Author(s):  
J E Bleasdale ◽  
J N Hawthorne ◽  
L Widlund ◽  
E Heilbronn
Keyword(s):  
Electrical Stimulation ◽  
Density Gradient ◽  
Synaptic Vesicles ◽  
Electric Organ ◽  
The Other ◽  
Torpedo Marmorata ◽  
Phospholipid Turnover ◽  
Unstimulated Control ◽  
The Brain

One electric organ of anaesthetized Torpedo marmorata was stimulated through electrodes placed on the electric lobe of the brain. Nerves to the other electric organ were cut to provide an unstimulated control. Glucose 6-[32P]phosphate was injected into each organ 16h before electrical stimulation. After stimulation for 10 min at 5 Hz, the organs were removed homogenized and centrifuged on a density gradient for the preparation of subcellular fractions. Stimulation increased the incorporation of 32P into phosphatidate, phosphatidylinositol and phosphatidylcholine. The increased phosphatidate labelling, but not that of the other two lipids, was seen in fractions rich in synaptic vesicles. Stimulation had no effect on ATP labelling. The phosphatidate content of most fractions fell slightly after stimulation, but amounts of other phospholipids were not affected.

scholarly journals Soluble low-Km 5′-nucleotidase from electric-ray (Torpedo marmorata) electric organ and bovine cerebral cortex is derived from the glycosyl-phosphatidylinositol-anchored ectoenzyme by phospholipase C cleavage

1992 ◽  
Vol 284 (3) ◽  
pp. 621-624 ◽  
Author(s):  
M Vogel ◽  
H Kowalewski ◽  
H Zimmermann ◽  
N M Hooper ◽  
A J Turner
Keyword(s):  
Cerebral Cortex ◽  
Phospholipase C ◽  
High Speed ◽  
Electric Organ ◽  
Bovine Brain ◽  
Soluble Enzyme ◽  
Torpedo Marmorata ◽  
Gpi Anchor ◽  
Glycosyl Phosphatidylinositol ◽  
Membrane Bound

Soluble and membrane-bound low-Km 5′-nucleotidase was isolated from high-speed supernatants and membrane fractions derived from the electric organ of the electric ray (Torpedo marmorata) or from bovine brain cerebral cortex. Purification of both enzymes included chromatography on concanavalin A-Sepharose and AMP-Sepharose. The contribution to the total of soluble enzyme activity was lower in electric organ (1.6%) than in bovine cerebral cortex (27.9%). Membrane-bound and soluble forms have very similar Km values for AMP and are inhibited by micromolar concentrations of ATP. Both forms cross-react with, and are inhibited by, an antibody against the membrane-bound surface-located (ecto-) 5′-nucleotidase from electric organ. The HNK-1 carbohydrate epitope is present on both forms of the Torpedo enzyme, but is entirely absent from bovine cerebral-cortex 5′-nucleotidase. An antibody specific for the inositol 1,2-(cyclic)monophosphate that is formed on phospholipase C cleavage of an intact glycosyl-phosphatidylinositol (GPI) anchor binds to the soluble, but not to the membrane-bound, form of the enzyme from both sources. Our results suggest that soluble low-Km 5′-nucleotidase in both electric organ and bovine brain is derived from the membrane-bound GPI-anchored form of the enzyme by the action of a phospholipase C and is not a soluble cytoplasmic enzyme.

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