1. L. Edvinsson and T. Skärby, Department of Clinical Pharmacology, University of Lund, Lund, Sweden; P. Tfelt-Hansen, Department of Neurology, Rigshospitalet, Copenhagen, Denmark; F. Gjerris, Department of Neurosurgery, Rigshospitalet, Copenhagen, Denmark; J. Olesen, Department of Neurology, Københavns amts Sygehus i Gentofte, Hellerup, Denmark