Effect of the nmda antagonist mk 801 on local cerebral blood flow in focal cerebral ischemia in the rat
Park, C.K.; Nehls, D.G.; Teasdale, G.M.; Mcculloch, J.
Journal of Cerebral Blood Flow and Metabolism 9(5): 617-622
ISSN/ISBN: 0271-678X Accession: 007262659
The effects of MK-801 upon local CBF after permanent middle cerebral artery (MCA) occlusion have been examined using [14C]iodoantipyrine autoradiography in halothane-anaesthetised rats. MK-801 (0.5 mg kg-1 i.v.) or saline was administered 30 min before MCA occlusion and CBF measured .apprx. 40 min after occlusion. In the hemisphere contralateral to the occluded MCA, MK-801 significantly reduced local CBF in 19 of the 22 regions examined from the levels in saline-treated rats. In the contralateral hemisphere, after treatment with MK-801, blood flow was reduced by an average of 37% with little variation in the magnitude of the reductions in different regions. In the hemisphere ipsilateral to MCA occlusion. MK-801 reduced CBF in almost every region located outside the territory of the occluded MCA. Within the territory of the occluded MCA, blood flow in the MK-801-treated rat did not significantly differ from values of vehicle-treated rats in any of the five cortical areas examined, although in the caudate nucleus there was a tendency for CBF to be lower in rats pretreated with MK-801. MK-801 had no effect on the amount of hypoperfused cerebral tissue (CBF < 30 ml 100 g-1 min-1) in the ipsilateral hemisphere at any coronal plane examined; e.g., at coronal plane anterior 7.2 mm, 51 .+-. 5% of the hemisphere displayed CBF of < 30 ml 100 g-1 min-1 in saline-treated rats with MCA occlusion compared with 52 .+-. 8% of the hemisphere in rats treated with MK-801 prior to MCA occlusion. Thus, the reported antiischaemic effects of MK-801 in this model cannot be attributed to improvement of blood flow to the hypoperfused cerebral tissue.