Amino acid osmolytes in regulatory volume decrease and isovolumetric regulation in brain cells

Contribution and mechanisms

Herminia Pasantes-Morales, Rodrigo Franco-Cruz, M. Eugenia Torres-Marquez, Karla Hernández-Fonseca, Arturo Ortega

Research output: Contribution to journalReview article

83 Citations (Scopus)

Abstract

Brain adaptation to hyposmolarity is accomplished by loss of both electrolytes and organic osmolytes, including amino acids, polyalcohols and methylamines. In brain in vivo, the organic osmolytes account for about 35% of the total solute loss. This review focus on the role of amino acids in cell volume regulation, in conditions of sudden hyposmosis, when cells respond by active regulatory volume decrease (RVD) or after gradual exposure to hyposmotic solutions, a condition where cell volume remains unchanged, named isovolumetric regulation (IVR). The amino acid efflux pathway during RVD is passive and is similar in many respects to the volume-activated anion pathway. The molecular identity of this pathway is still unknown, but the anion exchanger and the phospholemman are good candidates in certain cells. The activation trigger of the osmosensitive amino acid pathway is unclear, but intracellular ionic strength seems to be critically involved. Tyrosine protein kinases markedly influence amino acid efflux during RVD and may play an important role in the transduction signaling cascades for osmosensitive amino acid fluxes. During IVR, amino acids, particularly taurine are promptly released with an efflux threshold markedly lower than that of K + , emphasizing their contribution (possibly as well as of other organic osmolytes) vs inorganic ions, in the osmolarity range corresponding to physiopathological conditions. Amino acid efflux also occurs in response to isosmotic swelling as that associated with ischemia or trauma. Characterization of the pathway involved in this type of swelling is hampered by the fact that most osmolyte amino acids are also neuroactive amino acids and may be released in response to stimuli concurrent with swelling, such as depolarization or intracellular Ca ++ elevation.

Original languageEnglish (US)
Pages (from-to)361-370
Number of pages10
JournalCellular Physiology and Biochemistry
Volume10
Issue number5-6
DOIs
StatePublished - Jan 1 2000

Fingerprint

Amino Acids
Brain
Cell Size
Osmolar Concentration
Anions
Methylamines
Taurine
Protein-Tyrosine Kinases
Electrolytes
Ischemia
Ions
Wounds and Injuries

Keywords

  • Brain edema
  • Hyponatremia
  • Osmolytes
  • Swelling
  • Taurine

ASJC Scopus subject areas

  • Physiology

Cite this

Amino acid osmolytes in regulatory volume decrease and isovolumetric regulation in brain cells : Contribution and mechanisms. / Pasantes-Morales, Herminia; Franco-Cruz, Rodrigo; Torres-Marquez, M. Eugenia; Hernández-Fonseca, Karla; Ortega, Arturo.

In: Cellular Physiology and Biochemistry, Vol. 10, No. 5-6, 01.01.2000, p. 361-370.

Research output: Contribution to journalReview article

Pasantes-Morales, Herminia ; Franco-Cruz, Rodrigo ; Torres-Marquez, M. Eugenia ; Hernández-Fonseca, Karla ; Ortega, Arturo. / Amino acid osmolytes in regulatory volume decrease and isovolumetric regulation in brain cells : Contribution and mechanisms. In: Cellular Physiology and Biochemistry. 2000 ; Vol. 10, No. 5-6. pp. 361-370.
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