Aging and the Passage of L-tyrosine, L-DOPA, and Inulin Into Mouse Brain Slices in Vitro

J Gerontol. 1975 Jan;30(1):33-40. doi: 10.1093/geronj/30.1.33.

Abstract

The effect of age on active transport of catecholamine precursors was studied in a healthy population of mature (12-mo.-old) and senescent (30-mo.-old) C57BL/6J male mice. No age differences were observed in uptake of L-(3H)-tyrosine IN VITRO by slices of hypothalamus, brain stem, and striatum at external concentrations equal to or greater than blood levels. However, age-related reductions were observed intermittently in the hypothalamus, brain stem, and striatum at very low concentrations of tyrosine (less than 10 pg/ml). No age differences were observed in incorporation of L-(3H)-tyrosine into hypothalamic proteins when corrected for intracellular uptake of L-(3H)-tyrosine. No age differences were observed in uptake of L-(3H)-DOPA. The possible contribution of age-related changes in extra-cellular space to decreased uptake was determined to be negligible by wash-out studies of tyrosine and by the uptake of inulin. A significant age-related increase of inulin uptake IN VITRO was observed under ionic conditions which minimize tissue swelling.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aging*
  • Animals
  • Biological Transport, Active
  • Brain / metabolism*
  • Brain Stem / metabolism
  • Corpus Striatum / metabolism
  • Hypothalamus / metabolism
  • In Vitro Techniques
  • Inulin / metabolism*
  • Levodopa / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Tritium
  • Tyrosine / metabolism*

Substances

  • Tritium
  • Tyrosine
  • Levodopa
  • Inulin