Effect of pentobarbital on cerebral regional venous O2 saturation heterogeneity

Arabinda K. Sinha, Oak Z. Chi, Harvey R. Weiss

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Observed venous O2 saturation inhomogeneity in the brain implies a microregional imbalance in O2 supply/consumption. We hypothesized that this heterogeneity should be decreased by pentobarbital anesthesia through a reduction in regional metabolic heterogeneity. Male, Long-Evans, ∼ 350 g rats were either anesthetized with 50 mg/kg pentobarbital (n = 10) or used as a conscious control group (n = 10, catheters inserted two hours earlier under ether anesthesia). In each rat, regional cerebral blood flow was determined by [14C]iodoantipyrine and regional arterial and venous O2 saturation were determined by microspectrophotometry. In the PB group, the mean blood pressure (107 ± 7 Torr), heart rate (362 ± 29 /min), average cerebral blood flow (63 ± 19 ml/min/100 g), and average cerebral O2 consumption (3.7 ± 1.2 ml O2/min/100 g) were lower than those values in the conscious group (128 ± 15, 474 ± 44, 112 ± 40, and 7 ± 3), respectively. O2 extraction did not change after pentobarbital anesthesia. However, the dispersion of venous O2 saturation narrowed. The distribution of O2 saturations in 373 cerebral veins of anesthetized rats had a significantly reduced coefficient of variation [C.V. = 100 × (S.D./mean = 13] as compared to a C.V. of 18 in 320 veins in conscious rats. Thus, pentobarbital anesthesia reduced the microregional venous O2 saturation inhomogeneity in the brain, creating a more uniform balance of oxygen supply and consumption.

Original languageEnglish (US)
Pages (from-to)146-150
Number of pages5
JournalBrain research
Issue number1
StatePublished - Sep 18 1992

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology


  • Brain
  • O supply/demand ratiol
  • Rat
  • Venous O saturation


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