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21 results on '"Sarpietro, M. G."'

15. HPLC analysis of cyclic adenosine diphosphate ribose and adenosine diphosphate ribose: determination of NAD+ metabolites in hippocampal membranes

Author

Casabona, G., Sturiale, L., L Episcopo, M. R., Raciti, G., Fazzio, A., Sarpietro, M. G., Armando Genazzani, Cambria, A., and Nicoletti, F.

Subjects
Male, Chromatography, Adenosine Diphosphate Ribose, Cyclic ADP-Ribose, Membranes, analogs /&/ derivatives/analysis, Animals, Chromatography, High Pressure Liquid, Cyclic ADP-Ribose, Hippocampus, metabolism, Male, Membranes, metabolism, NAD, metabolism, Rats, Rats, Sprague-Dawley, NAD, Hippocampus, Rats, Rats, Sprague-Dawley, High Pressure Liquid, Animals, analogs /&/ derivatives/analysis, metabolism, Chromatography, High Pressure Liquid
Abstract

Cyclic adenosine diphosphate-ribose (cADPR) and ADPR were separated by high-performance liquid chromatography (HPLC) on a CarboPac PA-1 column at strong basic pH and quantitated by a pulsed amperometric detector. Although this HPLC method was quite sensitive and highly reproducible, it did not allow the separation of cADPR from guanosine monophosphate (GMP) which, when present, could be removed by ion-affinity chromatography, using gel-immobilized Fe3+ columns. Crude synaptic membranes from rat hippocampi were incubated with nicotinamide adenine dinucleotide (NAD) and acidic extracts were subject to HPLC analysis after neutralization. Incubation led to a time-dependent formation of ADPR, which was amplified when membranes were incubated in the presence of guanosine trisphosphate (GTP), guanosine-5'-0-(3-thiotrisphosphate) (GTP-gamma-S) or AlF3. cADPR did not accumulate in detectable amounts and only a minimal proportion (5%) of radioactivity originating from [3H]NAD co-eluted with authentic cADPR in extracts from hippocampal membranes. The simultaneous detection of cADPR and ADPR we have described may help the search for inhibitors of cADPR metabolism, which will allow to measure the cADPR that accumulates under basal conditions or in response to extracellular signals.

Published
1995

19. Interaction of resveratrol analogues with biomembrane models: A calorimetric study on structural variations effects

Author

Sarpietro, M. G., Spatafora, C., Ottimo, S., Corrado Tringali, and Castelli, F.

Subjects
lcsh:Food processing and manufacture, resveratrol derivative, lcsh:TP368-456, Resveratrol, liposome, biomembrane model, DSC
Abstract

Differential Scanning Calorimetry was used to study the interaction of new resveratrol derivatives using dimyristoylphosphatidylcholine (DMPC) multilamellar vesicles (MLV) as biomembrane models. MLV prepared in the presence of increasing molar fractions of the following compounds: (A) 3,5,3’,5’- tetramethoxystilbene, (B) 3,5,3’,4’-tetramethoxystilbene, (C) 3,4,5,4’-tetramethoxystilbene, (D) 3,4,5,3’,5’- pentamethoxystilbene and (E) 3,4,2’,4’,5’-pentamethoxystilbene were analyzed to study the effects exerted by the number and position of the substituents on the variations of thermotropic properties of the biomembrane model. The results showed that the number and the position of the substituent strongly affected the interaction between the compounds and the MLV based on DMPC. Kinetic experiments demonstrated that, the absorption of compounds A to E is limited in an aqueous medium. The presence of a lipophilic medium improves the absorption of the compounds by the biomembrane model.

21. Correlation between monoamino oxidase inhibitor activity of some thiazol-2-ylhydrazines and their interaction with dipalmitoylphosphatidylcholine liposomes.

Author

Castelli F, Pignatello R, Sarpietro MG, Mazzone P, Raciti G, and Mazzone G

Subjects
Animals, Brain enzymology, Calorimetry, Differential Scanning, Hydrazines chemistry, In Vitro Techniques, Membrane Fluidity, Membranes, Artificial, Monoamine Oxidase Inhibitors chemistry, Rats, Structure-Activity Relationship, Thermodynamics, Thiazoles chemistry, 1,2-Dipalmitoylphosphatidylcholine chemistry, Hydrazines pharmacology, Liposomes chemistry, Monoamine Oxidase Inhibitors pharmacology, Thiazoles pharmacology
Abstract

A calorimetric investigation has been carried out on the influence exerted by some 1-(alkoxybenzoyl)-2-(4-substituted thiazolyl-2-yl)hydrazines, possessing monoamine oxidase inhibitory (MAOI) activity, on the thermotropic behavior of model membranes constituted by dipalmitoylphosphatidylcholine (DPPC) vesicles. Attention was paid to evaluate how structural variations of drugs may influence drug-lipid interaction. The examined drugs were found to modify the gel to liquid-crystal phase transition of DPPC liposomes, by causing a shift of the transition temperature (Tm) toward lower values and a negligible variation in the enthalpy changes (delta H). The different effects on DPPC thermotropic behavior of these MAOI drugs could be considered in terms of different substituents on the molecule's backbone. The calorimetric results were related to drug's MAO inhibitory activity measured by fluorescence techniques and the apparent distribution coefficient of the compounds in water/n-octanol. A hypothesis on a correlation between a drug's structure, inhibitory activity, and membrane interaction has been suggested.

Published
1994
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