[3H]Methotrexate loss from the rat brain following enhanced uptake by osmotic opening of the blood-brain barrier

M. Ohata, W. R. Fredericks, Edward Neuwelt

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Right brain regions of anesthetized rats were loaded [3,5,7-3H]methotrexate ([3H]MTX) or with [14C]sucrose by infusing the tracers into the right carotid artery, after the blood-brain barrier had been opened by right carotid infusion of a hypertonic arabinose solution. During the 6 hr following the procedure, the [3H]MTX concentration in 7 right-sided brain regions, when normalized to the plasma concentration integral during tracer infusion, fell, with an average half-time of 4.8 hr as compared to less than 20 min for the initial rate of loss of [14C]sucrose. Right-left brain concentration differences 3 hr after treatment were statistically significant (p 3H]MTX but not for [14C]sucrose. The results indicate that intracerebral [3H]MTX is lost more slowly than is intracerebral [14C]sucrose, possibly because [3H]MTX enters brain cells, whereas [14C]sucrose remains largely extracellular.

Original languageEnglish (US)
Pages (from-to)1092-1096
Number of pages5
JournalCancer Research
Issue number3
Publication statusPublished - 1985
Externally publishedYes


ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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