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Acta Neuropathologica

, Volume 93, Issue 4, pp 354–368 | Cite as

Cerebral cortex blood flow and vascular smooth muscle contractility in a rat model of ischemia: a correlative laser Doppler flowmetric and scanning electron microscopic study

  • Akihiro Takahashi
  • H. K. Park
  • Miguel A. Melgar
  • Luis Alcocer
  • Jaime Pinto
  • Tiffanee Lenzi
  • Fernando G. Diaz
  • José A. Rafols
Regular paper

Abstract

The present study was undertaken to ascertain the role of smooth muscles and pericytes in the microcirculation during hyperperfusion and hypoperfusion following ischemia in rats. Paired external carotids, the pterygopalatine branch of the internal carotids and the basilar artery were exposed and divided. Reversible inflatable occluders were placed around the common carotids. After 24 h, the unanesthetized rat underwent 10-min ischemia by inflating the occluders. Continuous cortical cerebral blood flow (c-CBF) was monitored by laser Doppler flowmetry. The measured c-CBF was below 20% of control (P < 0.001) during ischemia. A c-CBF of 227.5 ± 54.1% (P < 0.001) was obtained during reperfusion hyperemia. A c-CBF of 59.7 ± 8.8% (P < 0.001) occurred at the nadir of postischemic hypoperfusion, and this was followed by a second hyperemia. The cytoarchitecture of the vascular smooth muscles and pericytes was assessed by scanning electron microscopy. Samples were prepared using a KOH-collagenase digestion method. In control rats, arteriolar muscle cells showed smooth surfaces. Capillary pericytes were closely apposed to the endothelium. Immediately after reperfusion, transverse membrane creases were observed on the smooth muscle surfaces. During maximal hyperemia the creases disappeared. When c-CBF started to decrease the creases became visible again. Throughout the postischemic hypoperfusion the creases remained. Capillary endothelial walls became tortuous in the late phase of hypoperfusion. During the second hyperemia most arteriolar muscle cells showed smooth surfaces. Some pericytes appeared to have migrated from the vascular wall. The morphological changes of smooth muscle membranes suggest that they are related to specific perfusional disturbances during ischemia and reperfusion.

Key words Reperfusion Cerebral blood flow Vascular smooth muscle cell Pericyte Scanning electron microscopy 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Akihiro Takahashi
    • 1
  • H. K. Park
    • 1
  • Miguel A. Melgar
    • 1
  • Luis Alcocer
    • 1
  • Jaime Pinto
    • 1
  • Tiffanee Lenzi
    • 2
  • Fernando G. Diaz
    • 1
  • José A. Rafols
    • 2
  1. 1.Department of Neurosurgery, Wayne State University School Medicine, University Health Center, 4201 St. Antoine 6E, Detroit, MI 48201, USA Tel.: 1-313-745-4661; Fax: 1-313-745-4099US
  2. 2.Department of Anatomy and Cell Biology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, USA Tel.: 1-313-577-41049; Fax: 1-313-577-3125; e-mail: jrafols@med.wayne.eduUS

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