The concentration of cytosolic free calcium was monitored in suspensions of intact human neutrophils in phosphate-buffered saline by means of the fluorescent indicator Indo 1 trapped in the cytosol. Trifluoperazine and n-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide markedly reduced the amplitude of the transient increase in cytosolic Ca2+ triggered by CaCl2 as well as by N-formyl-methionyl-leucyl-phenylalanine. The effect of the calmodulin antagonists on the calcium burst observed upon cell activation was much more pronounced in the presence of extracellular free calcium than in EGTA-containing media; it was not inhibited by wortmannin or thapsigargin. Nevertheless, trifluoperazine and n-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide inhibited the plasma-membrane Ca2+ ATPase if added to plasma membrane-enriched fractions of neutrophils. These results suggest that calmodulin antagonists affect calcium ion influx even if they inhibit plasma membrane Ca2+ ATPase.

Effect of calmodulin antagonists on calcium pump and cytosolic calcium level in human neutrophils / Capuozzo, Elisabetta; Verginelli, D.; Crifo', Carlo; Salerno, Costantino. - In: BIOCHIMICA ET BIOPHYSICA ACTA. - ISSN 0006-3002. - STAMPA. - 1357:(1997), pp. 123-127. [10.1016/S0167-4889(97)00021-9]

Effect of calmodulin antagonists on calcium pump and cytosolic calcium level in human neutrophils.

CAPUOZZO, Elisabetta;CRIFO', Carlo;SALERNO, Costantino
1997

Abstract

The concentration of cytosolic free calcium was monitored in suspensions of intact human neutrophils in phosphate-buffered saline by means of the fluorescent indicator Indo 1 trapped in the cytosol. Trifluoperazine and n-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide markedly reduced the amplitude of the transient increase in cytosolic Ca2+ triggered by CaCl2 as well as by N-formyl-methionyl-leucyl-phenylalanine. The effect of the calmodulin antagonists on the calcium burst observed upon cell activation was much more pronounced in the presence of extracellular free calcium than in EGTA-containing media; it was not inhibited by wortmannin or thapsigargin. Nevertheless, trifluoperazine and n-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide inhibited the plasma-membrane Ca2+ ATPase if added to plasma membrane-enriched fractions of neutrophils. These results suggest that calmodulin antagonists affect calcium ion influx even if they inhibit plasma membrane Ca2+ ATPase.
1997
Neutrophil; Calcium channel; Calcium homeostasis; Ca ATPase; Trifluoperazine
01 Pubblicazione su rivista::01a Articolo in rivista
Effect of calmodulin antagonists on calcium pump and cytosolic calcium level in human neutrophils / Capuozzo, Elisabetta; Verginelli, D.; Crifo', Carlo; Salerno, Costantino. - In: BIOCHIMICA ET BIOPHYSICA ACTA. - ISSN 0006-3002. - STAMPA. - 1357:(1997), pp. 123-127. [10.1016/S0167-4889(97)00021-9]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/253767
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