Effects of l-glutamic acid, gamma-aminobutiric acid and kainic acid on the surface electrical charge and enzyme activity of rat brain synaptosomes

Doltchinkova, Virjinia; Shkodrova, Milena; Mouleshkova, Nevena; Stoylov, Stoyl P.

doi:10.1063/1.5091387

Cited by 1 publication

(3 citation statements)

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“…Electrokinetic data for synaptosomes acquired here provide information about the dependence of their EPM and surface electrical charge on L-Glu and KA concentrations in the buffer. Our previous results of the EPM of synaptosomes isolated from cerebral cortex, suspended in a saline-sorbitol buffer with low ionic strength in the presence of L-Glu and KA, have shown strong volume changes in synaptosomes in the presence of the neurotransmitters studied [11]. There are numerous phenomenological data that seek to elucidate the coupling mechanism between hypothetical membrane sensors responding to changes in volume and executive transport systems, but, in practice, this mechanism is not fully clarified.…”

Section: Discussionmentioning

confidence: 99%

“…The rapid development of chemistry and pharmacology has led to the synthesis and testing of a huge number of chemical compounds, with direct or indirect influence on the CNS [10]. Despite the success of the study of the effects of such compounds at the organism or organ level, the mechanisms of their action at the subcellular level are not sufficiently elucidated [11].…”

Section: Introductionmentioning

confidence: 99%

“…Synaptosomes carry a negative charge at physiological pH [11,[28][29][30][31]. Their isoelectric point is determined at pH 4.0 [29].…”

Section: Introductionmentioning

confidence: 99%

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Surface Properties of Synaptosomes in the Presence of L-Glutamic and Kainic Acids: In Vitro Alteration of the ATPase and Acetylcholinesterase Activities

2021

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Morphologically and functionally identical to brain synapses, the nerve ending particles synaptosomes are biochemically derived membrane structures responsible for the transmission of neural information. Their surface and mechanical properties, measured in vitro, provide useful information about the functional activity of synapses in the brain in vivo. Glutamate and kainic acid are of particular interest because of their role in brain pathology (including causing seizure, migraine, ischemic stroke, aneurysmal subarachnoid hemorrhage, intracerebral hematoma, traumatic brain injury and stroke). The effects of the excitatory neurotransmitter L-glutamic acid and its agonist kainic acid are tested on Na+, K+-ATPase and Mg2+-ATPase activities in synaptic membranes prepared from the cerebral cortex of rat brain tissue. The surface parameters of synaptosome preparations from the cerebral cortex in the presence of L-glutamic and kainic acids are studied by microelectrophoresis for the first time. The studied neurotransmitters promote a significant increase in the electrophoretic mobility and surface electrical charge of synaptosomes at 1–4 h after isolation. The measured decrease in the bending modulus of model bimolecular membranes composed of monounsaturated lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine provides evidence for softer membranes in the presence of L-glutamate. Kainic acid does not affect membrane mechanical stability even at ten-fold higher concentrations. Both the L-glutamic and kainic acids reduce acetylcholinesterase activity and deviation from the normal functions of neurotransmission in synapses is presumed. The presented results regarding the modulation of the enzyme activity of synaptic membranes and surface properties of synaptosomes are expected by biochemical and biophysical studies to contribute to the elucidation of the molecular mechanisms of neurotransmitters/agonists’ action on membranes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%