Traumatic brain injury reduces myogenic responses in pressurized rodent middle cerebral arteries

Babu P. Mathew, Douglas Dewitt, Robert M. Bryan, Richard D. Bukoski, Donald Prough

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Traumatic brain injury (TBI) reduces cerebral vascular pressure autoregulation in experimental animals and in patients. In order to understand better the mechanisms of impaired autoregulation, we measured myogenic responses to changes in intraluminal pressure in vitro in pressurized, rodent middle cerebral arteries (MCAs) harvested after TBI. In an approved study, male Sprague-Dawley rats (275-400 g) were anesthetized, intubated, ventilated with 2.0% isoflurane in O2/air, and prepared for fluid percussion TBI. The isoflurane concentration was reduced to 1.5%, and rats (n = 6 per group) were randomly assigned to receive sham TBI followed by decapitation 5 or 30 min later or moderate TBI (2.0 atm) followed by decapitation 5 or 30 min later. After decapitation, MCA segments were removed, mounted on an arteriograph, and pressurized. MCA diameters were measured as transmural pressure was sequentially reduced. MCA diameters remained constant or increased in the sham groups as intraluminal pressure was reduced from 100 to 40 mm Hg. In both TBI groups, diameter decreased with each reduction in pressure. In summary, MCAs removed from uninjured, isoflurane-anesthetized rats had normal vasodilatory responses to decreased intraluminal pressure. In contrast, after TBI, myogenic vasodilatory responses were significantly reduced within 5 min of TBI and the impaired myogenic responses persisted for at least 30 min after TBI.

Original languageEnglish (US)
Pages (from-to)1177-1186
Number of pages10
JournalJournal of Neurotrauma
Volume16
Issue number12
StatePublished - Dec 1999

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Keywords

  • Autoregulation
  • Cerebral arteries
  • Myogenic response
  • Traumatic brain injury

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

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