Keywords: Inflammatory responses after cerebral ischemia are important for the development of final infarct size but the role of polymorphonuclear cells (PMN) is still a matter of debate; since previously used antibodies were recently declared as non-specific; In the present study; we investigated the temporo-spatial localization of PMN related to the neurovascular unit using specific antibodies; 7/4 and Ly6G; and application of G-CSF to induce proliferation and mobilization of PMN precursors after transient focal cerebral ischemia in mice; Infarct volumes; sensorimotor function; neurological outcome and immunohistochemical analysis of PMN were performed after G-CSF administration or placebo treatment; G-CSF-treated mice showed reduced infarct size (51.15±15.68 mm(2) vs; 39.31±16.13 mm(2) at day 1; 50.11±16.68 mm(2) vs; 33.16±4.86 mm(2) at day 4; p<0.05); They showed improved motor-function recovery and had a significantly better outcome compared to placebo-treated animals; Comparison of the two PMN detecting antibodies showed no difference in saturation plots or cell quantification; Studying the basement membrane-associated localization revealed ca; 60% extravascular PMN; independent of G-CSF administration; Extravascular PMNs were without any connection to laminin; but all near to the vessels; We conclude that 7/4 is a suitable marker to investigate PMN compared to Ly6G; which confirms results from former studies using the 7/4-antibody; Furthermore we report the observation that PMN were detected outside the laminin barrier but almost exclusively in close vicinity to the neurovascular unit