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We studied the effect of acetyl-L-carnitine (ALCAR) on dopamine release and the effect of long-term acetyl-L-carnitine treatment on age-related changes in striatal dopamine receptors and brain amino acid levels. In striatal tissue that had been incubated with [3H]dopamine, acetyl-L-carnitine increased the release of [3H]dopamine evoked by electrical(More)
In an open-label study, glycine was administered orally (10.8 g/day in three divided doses) to six chronically psychotic patients, as an adjunct to conventional neuroleptic therapy, for periods extending from 4 days to 8 weeks. Glycine was administered in an effort to facilitate endogenous glutamatergic transmission at the level of the N-methyl-D-aspartate(More)
Glutamate and related amino acids were determined in 53 discrete brain areas of 3- and 29-month-old male Fischer 344 rats microdissected with the punch technique. The levels of amino acids showed high regional variation - the ratio of the highest to lowest level was 9 for aspartate, 5 for glutamate, 6 for glutamine, and 21 for GABA. Several areas were found(More)
Taurine (Tau) and the small neutral amino acids glycine (Gly), serine (Ser), threonine (Thr), and alanine (Ala) were measured in 53 brain areas of 3- and 29-month-old male Fisher 344 rats. The ratio of highest to lowest level was 34 for Tau, 9.1 for Thr, 7.6 for Gly and Ser, and 6.5 for Ala. The heterogeneity was found in numerous areas; for example, Tau(More)
We measured the activity of cathepsin D, the major cerebral protease, in 50 separate areas of the central nervous system of adult and aged humans, using hemoglobin as the substrate. The activity showed significant regional heterogeneity, with average differences of 50-100% between the lower and higher level areas, and a more than threefold difference(More)
We measured changes in protease activity with aging, conducting assays of cathepsin D and calpain II activities and the rate of degradation of cytoskeletal proteins, preparing the enzymes and substrates from young and aged brains. Calpain preparations added to the young and to the aged substrates were standardized with casein as substrate so that(More)
The activity of cathepsin D on hemoglobin and on cytoplasmic tubulin was measured in brain preparations at different ages--in newborn, 10- and 21-day-old, and young adult rats. Enzyme activity increased after birth, reaching a maximum at around 21 days, and then declined. This increase was not parallel with decreased turnover of proteins during development,(More)
Cathepsin D-like activity in homogenates of five brain areas of 3-month-old and 24-month-old Fischer 344 rats was measured. With hemoglobin as substrate at pH 3.2, more than 90% of the activity was inhibited by pepstatin. In each area studied, activity was more than twice as high in the old rat brain: 140-160% higher in the cortex, cerebellum, pons-medulla,(More)
In previous studies on rat brain we found that the observed heterogeneity of the regional distribution of amino acids was much greater when small well-defined anatomical structures were assayed. We therefore reinvestigated the distribution of glutamate and aspartate in 50 discrete areas from adult and old human brain. The concentration of glutamate in the(More)
The regional distribution of seven amino acids thought to have inhibitory neurotransmitter or neurotransmitter precursor function--GABA, glycine, taurine, serine, threonine, phenylalanine, and tyrosine--was determined in 52 discrete areas from brain of adult and old humans. Significant heterogeneity was found, with 3- to 16-fold differences in levels in the(More)