Synaptosomes Properties

The antioxidant property of ferulic acid and related compounds from rice bran was reported by Kikuzaki et al, (2002). Their results indicated that these compounds elicit their antioxidant function through radical scavenging activity and their affinity with lipid substrates. Another recent study reported by Butterfield et al, (2002) demonstrated that ferulic acid offers antioxidant protection against hydroxyl and peroxyl radical oxidation in synaptosomal and neuronal cell culture systems in vitro. The effect of ferulic acid on blood pressure (BP) was investigated in spontaneously hypertensive rats (SHR). After oral administration of ferulic acid the systolic blood pressure (SBP) decreased in a dose-dependent manner. There was a significant correlation between plasma ferulic acid and changes in the SBP of the tail artery, suggesting... 

Gleitz J, Friese J, Beile A, Ameri A, Peters T. (1996a). Anticonvulsive action of (+/-)-kavain estimated from its properties on stimulated synaptosomes and Na-i- channel receptor sites. EurJ Pharmacol. Nov. 7. 315(1) 89-97. 

Risk, M., et al., Actions of Ptychodiscus brevis red tide toxin on metabolic and transmitter-releasing properties of synaptosomes, J. Neurochem., 39, 5, 1485, 1982. 

The superfusion of isolated nerve terminals ( synaptosomes ) is a widely used technique for interrogating the pharmacological properties of presynaptic receptors and their biochemical mechanisms. Physiological buffer continuously flows over a layer of synaptosomes loaded with radiolabelled transmitter, such that released transmitter is removed in the perfusate and collected. A key feature of this methodology is that it eliminates transmitter crosstalk between different boutons, enabling presynaptic events to be studied in isolation (Raiteri and Raiteri 2000). 

Adaptation of the nervous system to temperature is likely to play a major role in governing the thermal tolerance ranges and thermal optima of animals (Cossins and Bowler, 1987). Conduction along axons and, particularly, transmission of signals at synapses are strongly affected by temperature. It is probable, therefore, that alterations in the properties of neural membranes will be found to correlate closely with changes in the thermal sensitivity of behavior. The nearly perfect homeoviscous adaptation of brain synaptosomes from differently... 

Boyd-KimbaU D, Castegna A, Sultana R, Poon HF, Petroze R, Lynn BC, Klein JB, Butterfield DA (2005a) Proteomic identification of proteins oxidized by Abeta(l-42) in synaptosomes implications for Alzheimer s disease. Brain Res 1044 206-215 Boyd-KimbaU D, Sultana R, Mohmmad-Abdul H, Butterfield DA (2004) Rodent Abeta(l-42) exhibits oxidative stress properties similar to those of human Abeta(l-42) ImpUcations for proposed mechanisms of toxicity. J Alzheimers Dis 6 515-525 Boyd-KimbaU D, Sultana R, Poon HF, Lynn BC, Casamenti F, Pepeu G, Klein JB, Butterfield DA (2005b) Proteomic identification of proteins specificaUy oxidized by intracerebral injection of amyloid beta-peptide (1-42) into rat brain imphcations for Alzheimer s disease. Neuroscience 132 313-324... 

Endogenous ligands for the cannabinoid receptor have not yet been identified. Arachidonylethanolamide, a new arachidonic acid derivative named anandamide, was isolated from porcine brain. Its structure was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by synthesis. It inhibits the specific binding of a labelled cannabinoid probe to synaptosomal membranes in a manner typical of competitive ligands, and produces a concentration-dependent inhibition of the electrically-evoked twitch response of the mouse vas deferens, a characteristic effect of psychotropic cannabinoids. Similar compounds were synthesized and their pharmacological properties were investigated. 

Heaton GM, Bachelard HS (1973) The kinetic properties of hexose transport into synaptosomes from guinea pig cerebral cortex. J Neurochem 27 1099-1108. 

Docosahexaenoic acid (DHA, 22 6n-3) is the most abundant polyunsaturated fatty acid (PUFA) acylated to the aminophospholipids phosphatidylethanolamine (PE) and phosphatidylserine (PS) in membranes of neurons within the central nervous system (CNS) (Naughton, 1981 Salem et al., 1986). It can occur in concentrations exceeding 30-mol% of the fatty acids (Salem, 1989). The high enrichment ofDHA in synaptosomes is especially striking and suggests that DHA has unique properties that are required for optimal neuronal function. This concentration in the CNS is even more remarkable when one considers that sources of n-3 fatty acids are disproportionately limited in the terrestrial food chain compared to the much more abundant n-6 fatty acids. 

In the experiments described in this report calcium conductance was measured in nerve terminals (synaptosomes) isolated from rat cerebral cortex. Calcium conductances in these subcellular particles have been characterized and described extensively by Blaustein and colleagues and it appears that synaptosomes possess many of the properties of in situ nerve terminals (4 -J7). 

Venlafaxine is a virtually non-selective inhibitor of the uptake of 5-HT and NE by rat brain synaptosomes. It is structurally related to gamfexine a compound with antidepressant and psychostimulant properties (fig. 4). The potency of venlafaxine to inhibit in vitro monoamine uptake is the same range as that of imipramine and desipramine under the experimental conditions described by Muth et al. [45] and Yardley et al. [46]. 

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