Induction of nitric oxide synthase activity in rodent brain following middle cerebral artery occlusion
1995; Elsevier BV; Volume: 194; Issue: 3 Linguagem: Inglês
10.1016/0304-3940(95)11752-i
ISSN1872-7972
AutoresTazuka Yoshida, Christian Waeber, Zhihong Huang, Michael A. Moskowitz,
Tópico(s)Neurological Disease Mechanisms and Treatments
ResumoThe conversion of l-[3H]arginine to l-[3H]citrulline in the absence of calcium can be used to assay selectively the activity of inducible nitric oxide synthase (NOS) in rat spleen homogenates 6 h after lipopolysaccharide administration. Using similar assay conditions, changes in inducible NOS activity were measured within ischemic brain tissue between 2 h and 7 days following permanent middle cerebral artery (MCA) occlusion in Sprague-Dawley rats and SV-129 mice. Total (constitutive and inducible) NOS activity was measured in the presence of 0.5 mM CaCl2. Whereas total NOS activity in rat decreased dramatically to 16% and 6% of baseline 6 and 12 h after MCA occlusion, inducible NOS activity remained undetectable before 2 days after occlusion, became maximal at 3 days, and decreased to less than 10% of maximal iNOS activity at 7 days. In the mouse, total NOS activity decreased after MCA occlusion but inducible NOS activity was undetectable from 2 h to 4 days after occlusion. Sustained NO production by inducible NOS activity does not contribute to ischemic injury within 24 h after MCA occlusion, but may contribute to infarct maturation 2–4 days after ischemia in some but not all species.
Referência(s)