Ovalbumin sensitization of guinea-pigs reduces fMLP-induced calcium signal in alveolar macrophages.
In this study we analyzed the N-formyl-Met-Leu-Phe (fMLP)-induced calcium signal in alveolar macrophages (AM) isolated from ovalbumin-sensitized (OA-sensitized AM) and naive (naive AM) guinea-pigs. Guinea-pigs were sensitized by subcutaneous injection of OA and AM were isolated by bronchoalveolar lavage 6 weeks thereafter. On the following day, we measured in resting and fMLP-stimulated cells: intracellular calcium concentration by fura-2 imaging analysis, forskolin-induced cyclic AMP production and superoxide dismutase inhibitable superoxide anion release of adherent AM. Resting calcium was 82+/-5.0 nM (n=217) and 144+/-9.3 nM (n=213, P<0.001) in naive and OA-sensitized AM respectively. fMLP (10(-11)-10(-7)M) induced a dose-dependent calcium increase, 10(-8)M being the maximal effective dose in both naive and OA-sensitized AM. However, at all doses tested, this fMLP effect was lower in OA-sensitized than in naive AM. While in resting condition 10(-5)M forskolin increased cyclic AMP both in naive and OA-sensitized AM, in fMPL-stimulated AM forskolin was effective only in OA-sensitized AM. Superoxide anion release measured 10 min after fMLP stimulus was higher in naive than in sensitized AM. These data suggest that the fMLP-induced intracellular signal is different in OA-sensitized AM compared to naive cells.
Failli
P
P
Department of Pharmacology, University of Florence, Italy. failli@server1.pharm.unifi.it
Bindi
D
D
Franceschelli
F
F
Tanini
A
A
Ciuffi
M
M
Mazzetti
L
L
Zilletti
L
L
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis; D004789:Enzyme Activation; D005456:Fluorescent Dyes; D016257:Fura-2; D006168:Guinea Pigs; D016676:Macrophages, Alveolar / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D008297:Male; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D010047:Ovalbumin / Q000008:administration & dosage*; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D005456:Fluorescent Dyes; D010566:Virulence Factors, Bordetella; D013481:Superoxides; D005576:Colforsin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010047:Ovalbumin; D000242:Cyclic AMP; D013482:Superoxide Dismutase; D000262:Adenylyl Cyclases; D002118:Calcium; D016257:Fura-2