Gα_i2 in neutrophils is responsible for chemokine-induced neutrophil arrest. Number of adherent leukocytes in cremaster muscle postcapillary venules of Gnai2^−/− → Gnai2^+/+ chimeric mice and Gnai2^+/+ mice after intravenous injection of 600 ng CXCL1 (normalized for blood neutrophil counts). Data were recorded and analyzed for 1 minute starting 15 seconds after CXCL1 injection. Data presented as means plus or minus SEM from at least 4 mice.