| 9227496 |
Ikejima K, Qu W, Stachlewitz RF, Thurman RG: Kupffer cells contain a glycine-gated chloride channel. . Am J Physiol. 1997 Jun;272(6 Pt 1):G1581-6.
Here the effect of glycine on intracellular Ca2+ concentration ([Ca2+] i) in cultured Kupffer cells stimulated with lipopolysaccharide (LPS) was investigated to assess the possibility that they contain a glycine-gated chloride channel. LPS (10 micrograms/ml) increased [Ca2+] i rapidly, with peak values reaching 307 +/- 29 nM. Glycine (1 mM) prevented this increase nearly completely. Low concentrations of strychnine (1 microM), a glycine receptor antagonist, reversed the inhibitory effect of glycine completely; however, high concentrations of strychnine (1 mM) mimicked glycine. The effects of glycine and high-dose strychnine were prevented when cells were incubated in chloride-free buffer. Furthermore, potassium (25 mM) and LPS depolarized the Kupffer cell plasma membrane, whereas glycine caused hyperpolarization and prevented depolarization due to potassium and LPS. Moreover, tumor necrosis factor-alpha (TNF-alpha) production in cultured Kupffer cells due to LPS was decreased significantly by glycine. Therefore, it is concluded that Kupffer cells contain a glycine-gated chloride channel similar to that described previously in the central nervous system. Prevention of increases in [Ca2+] i due to LPS by activation of chloride influx reduced synthesis and release of toxic mediators by Kupffer cells. |
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