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Full-Text Articles in Medicine and Health Sciences
Osmosensitive Release Of Neurotransmitter Amino Acids: Relevance And Mechanisms, Herminia Pasantes-Morales, Rodrigo Franco, Lenin Ochoa, Benito Ordaz
Osmosensitive Release Of Neurotransmitter Amino Acids: Relevance And Mechanisms, Herminia Pasantes-Morales, Rodrigo Franco, Lenin Ochoa, Benito Ordaz
School of Veterinary and Biomedical Sciences: Faculty Publications
Hyposmolarity activates amino acid efflux as part of the corrective volume process in a variety of cells. This review discusses the mechanism of amino acid release in brain cells preparations. Results present evidence of substantial differences between the efflux of taurine and that of GABA and glu-tamate, which besides a possible role as osmolytes, have a main function as synaptic transmitters. The differences found concern the efflux time course, the sensitivity to Cl– channel blockers, the modulation by tyrosine kinases, the influence of PKC and the effect of cytoskeleton disruptive agents. While taurine efflux features fit well with the …
Influence Of Protein Tyrosine Kinases On Cell Volume Change-Induced Taurine Release, Herminia Pasantes-Morales, Rodrigo Franco
Influence Of Protein Tyrosine Kinases On Cell Volume Change-Induced Taurine Release, Herminia Pasantes-Morales, Rodrigo Franco
School of Veterinary and Biomedical Sciences: Faculty Publications
Taurine efflux occurs in association with cell swelling in both hyposmotic and isosmotic conditions and during cell shrinkage in apoptotic death. Release occurs through a leak pathway, is largely Ca2+-independent and is sensitive to Cl– channel blockers. Taurine efflux elicited by hyposmolarity is reduced or suppressed by tyrosine kinase blockers and increased by tyrosine phosphatase inhibitors. The specific kinases involved are still unknown and may be different in the various cell types. Non-receptor and scr-related protein kinases have been identified in some cells as elements that directly phosphorylate the taurine efflux pathway. Possible tyrosine kinase targets are …
Mechanisms Counteracting Swelling In Brain Cells During Hyponatremia, Herminia Pasantes-Morales, Rodrigo Franco, Benito Ordaz, Lenin D. Ochoa
Mechanisms Counteracting Swelling In Brain Cells During Hyponatremia, Herminia Pasantes-Morales, Rodrigo Franco, Benito Ordaz, Lenin D. Ochoa
School of Veterinary and Biomedical Sciences: Faculty Publications
Water gain in the brain consequent to hyponatremia is counteracted by mechanisms that initially include a compensatory displacement of liquid from the interstitial space to cerebrospinal fluid and systemic circulation and subsequently an active reduction in cell water accomplished by extrusion of intracellular osmolytes to reach osmotic equilibrium. Potassium (K+), chloride (Cl–), amino acids, polyalcohols, and methylamines all contribute to volume regulation, with a major contribution of ions at the early phase and of organic osmolytes at the late phase of the regulatory process. Experimental models in vitro show that osmolyte fluxes occur via leak pathways …
Evidence For Two Mechanisms Of Amino Acid Osmolyte Release From Hippocampal Slices, R. Franco, M. E. Torres-Marquez, H. Pasantes-Morales
Evidence For Two Mechanisms Of Amino Acid Osmolyte Release From Hippocampal Slices, R. Franco, M. E. Torres-Marquez, H. Pasantes-Morales
School of Veterinary and Biomedical Sciences: Faculty Publications
A 30% decrease in osmolarity stimulated 3H-taurine, 3H-GABA and glutamate (followed as 3H-D-aspartate) efflux from rat hippocampal slices. 3H-taurine efflux was activated rapidly but inactivated slowly. It was decreased markedly by 100 μM 5-nitro-(3-phenylpropylamino) benzoic acid (NPPB) and 600 μM niflumic acid and inhibited strongly by tyrphostins AG18, AG879 and AG112 (25–100 μM), suggesting a tyrosine kinase-mediated mechanism. Hyposmolarity activated the mitogen-activated protein kinases (MAPK) extracellular-signal-related kinase-1/2 (ERK1/ERK2) and p38, but blockade of this reaction did not affect 3H-taurine efflux. Hyposmosis also activated phosphatidyl-inositide 3-kinase (PI3K) and its prevention by wortmannin (100 nM) essentially abolished …