English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Endogenous oploids seem to play important roles in the regulation of the development of the nervous system (Hauser et al.. 1987), Opioid peptides have been described as natural trophic factors in brain development and several studies have reported opioid-induced alterations in neural growth, Enkephalins, the first endogenous opioid peptides isolated, participate in the regulation of growth in the developing rat nervous system (Zagon et aI., 1994) and also serves as a growth factor (Zagon et al.. 1993). It is known that the effects of enkephalins are of short duration. as a resu~ of their hydrolysis by brain enzymes. A major pathway of enkephalin degradation occurs via the cleavage of the Tyr-Gly amide bond by aminopeptidases (Thorsett and Wivrat, 1987). Three aminopeptidases have high affinity for enkephalins (Hersh, 1982); one soluble (Dyer et al" 1990) and two membrane-bound, puromycin-sensitive (or aminopeptidase Mil) and puromycininsensitive (or aminopeptidase M) (Giros et al" 1985). Nowadays. it is accepted that this proteolytic group is involved in the maturation of the rat brain (Gandarias et at., 1989). The establishment of the subcellular localization of enkephalin-degrading enzymes and their eventual changes during the development are important for understanding the regulatory mechanism controlling the activity of enkephalins. Male Sprague-Dawley rats were used in this investigation. The ages of the animals were embryonic day 22. parturition day (PO) and postnatal days 2, 4 and 6. The animalswere perfused under Equithensinanaesthesia withsaline (pH7.4). Brain subcortices were taken by dissection and homogenized in 10 volumes of 0.32 M sucrose. Subcellular fractions were obtained according to the method of Gray and Whittaker (1962), modified by Krueger et al. (1977). Briefly, from the crude mitochondrial pellet (12,500 g), we obtained fractions A (myelin), B (synaptosomal) and C (mitochondriai). Fractions B, C, and microsomal pellet (100,000 g) and sampies from crude nuclear pellet (1000 g), were homogenized in Tris.HC110 mM (pH 7.4) and centrifuged (100,000 g, 30 min, 40C). Samples from these supernatants and those previously obtained at 100.000 g (cytosol) were used to detect soluble activity and proteins. The resu~ant pellets and fraction A (myelin) were homogenized in Tris.HC110 mM (pH 7.4), plus 1% of Triton X-100 to obtain, after centrifugation (100,000 g, 30 min 40C), supernatants which were employed to detect membrane-boundactivity and proteins. Tyr.aminopeptidaseactivity was fluorimetrically measured by a modification in the method of Greenberg (1962), using Tyr-~-naphthylamide as substrate. The membrane.bound activity was detected entirely and after incubating with 20 ~M puromycin. Protein concentration was measured by the method of Bradford (1976). The results were analyzed by the analysis of the variance and the comparison between means was done by Fisher's test.

Developmental changes of Tyr-aminopeptidase activity in different subcellular fractions of the subcortical region of the rat brain.