scholarly journals The stimulation by transmitter substances and putative transmitter substances of the net activity of phospholipase A2 of synaptic membranes of cortex of guinea-pig brain

1975 ◽  
Vol 148 (2) ◽  
pp. 197-208 ◽  
Author(s):  
R J Gullis ◽  
C E Rowe
Keyword(s):  
Guinea Pig ◽  
Phospholipase A2 ◽  
Synaptic Vesicles ◽  
Optimum Concentration ◽  
Synaptic Membranes ◽  
Phospholipase A1 ◽  
Response Curves ◽  
Pig Brain ◽  
Hydrolysis Of ◽  
Guinea Pig Brain

1. The distribution of the hydrolyses of phosphatidylcholine by phospholipase A2 and phospholipase A1, and the hydrolysis of lysophosphatidylcholine by lysophospholipase, in subcellular and subsynaptosomal fractions of cerebral cortices of guinea-pig brain, was determined. 2. Noradrenaline stimulated hydrolysis by phospholipase A2 in whole synaptosomes, synaptic membranes and fractions containing synaptic vesicles. 3. Stimulation of hydrolysis by phospholipase A2 in synaptic membranes by noradrenaline was enhanced by CaCl2, and by a mixture of ATP and MgCl2. The optimum concentration of CaCl2, in the presence of ATP and MgCl2, for stimulation by 10 muM-noradrenaline was in the range 1-10muM. The optimum concentration for ATP-2MgCl2 in the presence of 1 muM-CaCl2 was in the range 0.1-1mM. 4. Hydrolysis by phospholipase A2 of synaptic membranes was also stimulated by acetylcholine, carbamoylcholine, 5-hydroxytryptamine, dopamine (3,4-dihydroxyphenethylamine), histamine, psi-aminobutyric acid, glutamic acid and aspartic acid. With appropriate concentrations of cofactors, sigmoidal dose-response curves were obtained, half-maximum stimulations being obtained with concentrations of stimulant in the range 0.1-1muM. 5. Taurine also stimulated hydrolysis of phosphatidylcholine by phospholipase A2. There were only slight stimulations with methylamine, ethylenediamine or spermidine. No stimulation was obtained with glucagon.

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 Glyceride lipases in nerve endings of guinea-pig brain and their stimulation by noradrenaline, 5-hydroxytryptamine and adrenaline

1973 ◽  
Vol 132 (2) ◽  
pp. 233-248 ◽  
Author(s):  
O. S. Vyvoda ◽  
C. E. Rowe
Keyword(s):  
Guinea Pig ◽  
Synaptic Vesicles ◽  
Protein Concentration ◽  
Synaptic Membranes ◽  
Ph Optimum ◽  
Triglyceride Lipase ◽  
Monoglyceride Lipase ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Guinea Pig Brain

1. Combined guinea-pig cortex and cerebellum was shown to contain triglyceride lipase, diglyceride lipase and monoglyceride lipase, which were assayed by the release of [1-14C]palmitate from [1-14C]palmitoylglycerol esters. Triglyceride lipase and diglyceride lipase were found in all particulate fractions. 2. With osmotically ruptured synaptosomes the rates of release of palmitate from glyceryl tripalmitate and glyceryl dipalmitate were 7–25μmol/h per g of protein and 0.18–0.69mmol/h per g of protein respectively. The logarithm of the rate of hydrolysis of glyceryl monopalmitate increased linearly with the logarithm of protein concentration. The pH optima of triglyceride lipase and diglyceride lipase were between 7 and 8. The pH optimum for monoglyceride lipase was approx. 8. 3. Triglyceride lipase and diglyceride lipase of osmotically ruptured synaptosomes were stimulated by noradrenaline, 5-hydroxytryptamine and adrenaline. Triglyceride lipase of isolated synaptic membranes was stimulated by 0.01–1mm-noradrenaline. Aging of membranes at 0°C decreased activity, which could still be stimulated by noradrenaline. Diglyceride lipase of isolated membranes was stimulated by 1μm–1mm-noradrenaline. The activity of triglyceride lipase in isolated synaptic vesicles was diminished by 1mm-5-hydroxytryptamine.

scholarly journals The stimulation by synaptic transmitters of the incorporation of oleate into the phospholipid of synaptic membranes

1975 ◽  
Vol 148 (3) ◽  
pp. 557-565 ◽  
Author(s):  
R J Gullis ◽  
C E Rowe
Keyword(s):  
Initial Rate ◽  
Optimum Concentration ◽  
Synaptic Membranes ◽  
Gamma Aminobutyric Acid ◽  
Response Curves ◽  
Ethanolamine Glycerophospholipids ◽  
Sodium Phosphate Buffer ◽  
Choline Glycerophospholipids ◽  
Hydrolysis Of ◽  
Guinea Pig Brain

Noradrenaline stimulated the incorporation of oleate into choline glycerophospholipids of guinea-pig brain synaptic membranes incubated in sodium phosphate buffer. In the presence of 1 mm-NaF, noradrenaline stimulated the incorporation of oleate into the choline glycerophospholipids, phosphatidylinositol, ethanolamine glycerophospholipids, phosphatidylserine and phosphatidic acid of synaptic membranes incubated in 10 mm-Tris-HCl buffer. In Tris-CHl containing 1 mm-NaF, stimulation of incorporation of oleate into choline glycerophospholipids by noradrenaline was enhanced by ATP, CaCl2, MgCl2 and CoA plus dithiothreitol. The optimum concentration of CaCl2 for stimulation by 10 mum-noradrenaline was 10 mum. In the presence of CaCl2, the optimum concentration of ATP-2MgCl2 was in the range 0.1-1 mm. Acetylcholine, carbamoylcholine, 5-hydroxytryptamine, dopamine, histamine and gamma-aminobutyric acid also stimulated the incorporation of oleate into choline glycerophospholipids of synaptic membranes. Sigmoidal dose-response curves were obtained, similar to those obtained previously for stimulation by the same agonists of the hydrolysis of phosphatidylcholine by phospholipase A2 (Gullis & Rowe, 1975a). The initial rate of transfer of oleate from oleoyl-CoA to choline glycerophospholipid was similar to the initial rate of transfer from oleate-albumin, stimulated by noradrenaline. Transfer of oleate from oleoyl-CoA was not appreciably stimulated by noradrenaline, but was stimulated by ATP and MgCl2.

scholarly journals NMDA RECEPTOR DOWN-REGULATION BY PHOSPHOLIPASE A2 IN THE FETAL GUINEA PIG BRAIN DURING HYPOXIA. • 2248

1996 ◽  
Vol 39 ◽  
pp. 377-377
Author(s):  
Om P Mishra ◽  
David Moon ◽  
Anli Zhu ◽  
Jane E McGowan ◽  
Maria Delivoria-Papadopoulos
Keyword(s):  
Nmda Receptor ◽  
Guinea Pig ◽  
Phospholipase A2 ◽  
Down Regulation ◽  
Pig Brain ◽  
Guinea Pig Brain

scholarly journals FREE-FLOW ELECTROPHORETIC SEPARATION AND ELECTRICAL SURFACE PROPERTIES OF SUBCELLULAR PARTICLES FROM GUINEA PIG BRAIN

1971 ◽  
Vol 49 (2) ◽  
pp. 235-246 ◽  
Author(s):  
K. J. Ryan ◽  
H. Kalant ◽  
E. Llewellyn Thomas
Keyword(s):  
Guinea Pig ◽  
Synaptic Vesicles ◽  
Succinic Dehydrogenase ◽  
Free Flow ◽  
Electrophoretic Separation ◽  
Charge Densities ◽  
Zeta Potentials ◽  
Pig Brain ◽  
Choline Acetylase ◽  
Guinea Pig Brain

Continuous free-flow electrophoretic separation has been used to obtain relatively pure preparations of synaptosomes and synaptic vesicles from crude fractions of guinea pig brain homogenates. Measurements of the contents of protein, neuraminic acid, and bound acetylcholine; the activities of succinic dehydrogenase, adenosine triphosphatase, choline acetylase, and 5'-nucleotidase; and the uptake of 14C-labeled choline arid acetylcholine in the presence and absence of hemicholinium, all confirm the electron microscope evidence that the electrophoretic preparations are at least as pure as those obtained by ultracentrifugal methods. The electrophoretic mobility measurements have been used to calculate zeta potentials and surface charge densities for these particles.

scholarly journals Net activity of phospholipase A2 in brain and the lack of stimulation of the phospholipase A2-acylation stem

1977 ◽  
Vol 164 (1) ◽  
pp. 287-288
Author(s):  
C E Rowe
Keyword(s):  
Cerebral Cortex ◽  
Cyclic Amp ◽  
Guinea Pig ◽  
Phospholipase A2 ◽  
Synaptic Membranes ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of ◽  
Stimulation Of

Certain observations reported previously from this laboratory have not proved reproducible. These are (1) the relatively rapid hydrolysis of added phosphatidylcholine by phospholipase A2 of tissue from the cerebral cortex of the guinea pig and (2) the stimulation by 10 micron-noradrenaline and by 1.0nM-cyclic AMP of the phospholipase A2-acylation system of isolated synaptic membranes.

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