Cl sup minus -HCO sup minus sub 3 antiport in rat lacrimal gland

Journal Article · Thu Sep 01 00:00:00 EDT 1988 · American Journal of Physiology; (USA)

OSTI ID:6828630

Lambert, R W; Bradley, M E; Mircheff, A K ^[1]

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1. Univ. of Southern California School of Medicine, Los Angeles (USA)

With the use of analytical subcellular fractionation and tracer uptake methods the authors have demonstrated the presence of a Cl{sup {minus}}-HCO{sup {minus}}{sub 3} antiport mechanism in the rat exorbital lacrimal gland. They find that outwardly directed gradients of HCO{sup {minus}}{sub 3} and of {sup 35}Cl{sup {minus}} accelerated the flux of {sup 36}Cl{sup {minus}} into isolated membrane vesicles. Because vesicle membrane potentials were clamped to 0 mV with K{sup +}-valinomycin, the observed anion gradient-dependent acceleration of Cl{sup {minus}} influx could not be attributed to conductive fluxes. The antiporter had an apparent K{sub 0.5} for Cl{sup {minus}} between 6 and 10 mM. It was sensitive to the stilbene derivatives 4-acetamido-4{prime}-isothiocyanostilbene-2,2{prime}-disulfonic acid (SITS) and 4,4{prime}-diisothiocyanostilbene-2,2{prime}-disulfonic acid (DIDS). It was also sensitive to the loop diuretic furosemide, which has frequently been used in tests for NaKCl{sub 2} symporter activity. Other anions inhibited anion gradient-driven Cl{sup {minus}} influx in the sequence SCN{sup {minus}} > NO{sup {minus}}{sub 3} > Cl{sup {minus}} HCO{sup {minus}}{sub 3} > SO{sup 2{minus}}{sub 4}. The density distribution of Cl{sup {minus}}-HCO{sup {minus}}{sub 3} antiport activity indicated that {approximately}80% of the transporter was associated with intracellular membranes, suggesting the presence of cytoplasmic pools of functional antiporters. Because several studies have already shown the presence of Na{sup +}-H{sup +} antiporter activity in lacrimal acinar cell basolateral membranes, a cellular model for lacrimal acinar electrolyte secretion is proposed in which a parallel array of Cl{sup {minus}}-HCO{sup {minus}}{sub 3} and Na{sup +}-H{sup +} antiporters mediates the Na{sup +}-dependent accumulation of Cl{sup {minus}} against its electrochemical potential gradient.

• OSTI ID: 6828630
• Journal Information: American Journal of Physiology; (USA), Vol. 255:3; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CHLORINE 36
MEMBRANE TRANSPORT
EPITHELIUM
ENZYME ACTIVITY
IONS
SECRETION
SODIUM 22
DIURETICS
LACRIMAL DUCTS
RATS
SULFONIC ACIDS
ALKALI METAL ISOTOPES
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
BODY AREAS
CHARGED PARTICLES
CHLORINE ISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
EYES
FACE
HEAD
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAMMALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
RADIOISOTOPES
RODENTS
SENSE ORGANS
SODIUM ISOTOPES
TISSUES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques