Ug. Friis et al., IGE-RECEPTOR ACTIVATED CHLORIDE UPTAKE IN RELATION TO HISTAMINE-SECRETION FROM RAT MAST-CELLS, British Journal of Pharmacology, 111(4), 1994, pp. 1179-1183
1 Antigen-stimulated histamine secretion from rat peritoneal mast cell
s was inhibited when extracellular chloride was replaced by either ise
thionate or gluconate anions, but the histamine release still remained
quite substantial. 2 Rat peritoneal mast cells take up Cl-36 and the
uptake reaches a steady state after 60 min incubation with the isotope
. At steady state, the intracellular chloride level in the cells was c
alculated to be 29 +/- 11.5 mM. 3 The chloride uptake in mast cells wa
s exponential with a rate constant of 0.036 min-1 in resting cells. Wh
en the cells were stimulated with antigen, and rate constant for chlor
ide uptake increased to 0.90 min-1: an increase of 25 fold. Under iden
tical experimental conditions histamine release increased 3 fold. 4 Th
e rate of chloride uptake in either resting cells or in antigen-stimul
ated cells was not changed when the extracellular medium was nominally
calcium-free but histamine release was almost completely inhibited in
the absence of extracellular calcium. 5 The putative chloride channel
blocker DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid) 0.
3 to 30 muM, produced a concentration-related inhibition of antigen-st
imulated histamine secretion but DIDS (30 muM) did not inhibit the ant
igen-stimulated increase of chloride uptake. 6 The cyclic AMP analogue
, dibutyryl cyclic AMP (1 mM) produced a delayed increase in chloride
uptake in resting mast cells but neither dibutyryl cyclic AMP nor 8-br
omo cyclic AMP per se induced any histamine secretion. 7 Ouabain (1 mM
) which inhibits the Na+/K+ ATPase in rat peritoneal mast cells, faile
d to affect the uptake of chloride in resting mast cells. 8 The Na/K/2
Cl-cotransport inhibitor, furosemide (0.7 mM), slowed the unstimulated
chloride uptake in resting mast cells and abolished the increased ant
igen-induced chloride uptake when added together with antigen. In cont
rast, spontaneous and antigen-induced histamine release were unaffecte
d by the presence of furosemide. However, when furosemide was added to
the cell suspension 5 min before stimulation, furosemide was without
effect on the antigen-induced chloride uptake. 9 In addition to the ch
loride uptake mediated by chloride channels which may be related to th
e mechanism of histamine secretion, crosslinking of the high affinity
membrane receptors for IgE is followed by a fast chloride uptake that
is likely to occur through a furosemide-sensitive Na/K/2Cl-cotransport
er.