title: Sustained decrease and remarkable increase in red blood cell velocity in intraparenchymal capillaries associated with potassium-induced cortical spreading depression.
abstract: OBJECTIVE
  To examine changes in red blood cell (RBC) velocity in intraparenchymal capillaries of rat cerebral cortex in response to KCl-induced cortical spreading depression (CSD).
  
  
  METHODS
  In isoflurane-anesthetized rats, the velocity of fluorescently labeled RBCs flowing in capillaries in layer I was measured with a high-speed camera laser-scanning confocal fluorescence microscope, with simultaneous monitoring of DC potential, the electroencephalogram (EEG), partial pressure of oxygen (PO(2) ), and cerebral blood flow (CBF).
  
  
  RESULTS
  After KCl application, a transient deflection of DC potential (i.e., CSD) repeatedly appeared concomitantly with depression of EEG, and was propagated in the distal direction. PO(2) transiently decreased and CBF was slowly elevated. The frequency distribution of RBC velocity was shifted downward during CSD and was still low after the passage of CSD. When we observed RBC velocity in 38 individual capillaries, 10 capillaries exhibited slowed-down RBC during CSD and RBC velocity remained low in 2 even after the passage of CSD. On the other hand, RBCs with moderately (<3 mm/sec) or remarkably (>3 mm/sec) increased velocities were seen in 10 and 5 capillaries, respectively.
  
  
  CONCLUSIONS
  CSD-induced excitation of neurons may sustainably decrease or greatly increase RBC velocity in capillaries.
authors: Department of Neurology, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan. unekawa.m@z5.keio.jp
authors: Miyuki
authors: M
authors: Unekawa
authors: Minoru
authors: M
authors: Tomita
authors: Yutaka
authors: Y
authors: Tomita
authors: Haruki
authors: H
authors: Toriumi
authors: Norihiro
authors: N
authors: Suzuki
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D002196:Capillaries / Q000502:physiology; D002540:Cerebral Cortex / Q000098:blood supply* / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004912:Erythrocytes; D008297:Male; D011189:Potassium Chloride / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D011189:Potassium Chloride