Publisher Summary This chapter discusses a study to elaborate the naloxone-stimulated high affinity uptake of Leu-enkephalin by glia-enriched fraction of the rabbit brain. As most of the labeled peptides from commercial sources are contaminated, chromatography on Sephade LH-20 was applied for purifying tritiated Leu-enk was used. After washing out the extra-glia pool, the retained glia cells were ruptured with water to obtain the intra-glia pool. Upon chromatography on Sephadex LH-20, most of the radioactivity in both pools was found to be tritiated tyrosine released from Leu-enk. Leu-enk is accumulated by glia-enriched fraction by high and low affinity uptake. High affinity uptake is stimulated by opiate antagonist, naloxon.
