enkephalin--leucine-2-alanine and Body-Weight

We studied the possibility of correction of the negative effects of antenatal hypoxia on the liver tissue homeostasis in 7-day-old albino rats by administration of opioid peptides in a dose of 100 μg/kg on postnatal days 2-6. Administration of mixed μ/δ-opioid receptor agonist Dalargin neutralized deviations of gravimetric indicators, parameters of proliferative activity, and activity of the nucleolar apparatus of hepatocytes. Administration of the non-opiate Leu-enkephalin analogue did not normalize gravimetric parameters and nucleolar apparatus parameters, however, it significantly increased the pool of proliferating hepatocytes. Both peptides significantly reduced the intensity of free radical oxidation, improved antioxidant antiradical defense and resistance to peroxidation in the liver tissue of animals subjected to antenatal hypoxia.

Topics: Animals; Animals, Newborn; Antioxidants; Body Weight; Cell Nucleus; Enkephalin, Leucine-2-Alanine; Female; Free Radicals; Hepatocytes; Homeostasis; Hypoxia; Liver; Opioid Peptides; Organ Size; Oxidative Stress; Rats; Rats, Wistar

The highest maximum binding capacities at the mu-sites of rabbit brain are in the striatum, with intermediate levels in the diencephalon, mesencephalon, cerebellum and cortex and low levels in the pons-medulla and hippocampus. For the delta-site the highest maximum binding capacity is also in the striatum; there are almost equally low levels in the other brain regions. At the kappa-sites the maximum binding capacities are highest in the diencephalon; there are intermediate levels in the cortex and striatum, and low levels in the mesencephalon, cerebellum, hippocampus and pons-medulla. The KD values lack reproducibility; there are no regional variations at the kappa-site as estimated with [3H](-)-bremazocine, but the possibility cannot be excluded that there are regional variations in the KD values for [3H][D-Ala2,MePhe4,Gly-ol5]enkephalin at the mu-site or for [3H][D-Ala2,D-Leu5]enkephalin at the delta-site. It may be important to use saturation analysis in future investigations of the distributions of the binding sites.

Topics: Analgesics; Animals; Benzomorphans; Binding, Competitive; Body Weight; Brain Chemistry; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Enkephalins; In Vitro Techniques; Male; Membranes; Nerve Tissue Proteins; Rabbits; Receptors, Opioid; Receptors, Opioid, delta; Receptors, Opioid, kappa; Receptors, Opioid, mu

Opiate receptors of the mu type were labeled with [125I]D-Ala2,N-Me-Phe4,Met-(O)5-ol-enkephalin (FK-33824). delta receptors were labeled with [125I]D-Ala2-D-Leu5-enkephalin (DADLE) in the presence of excess (N-Me-Phe3,D-Pro4)-morphiceptin (PL017). Since DADLE binds mu and delta receptor sites, and PL017 blocks mu receptors, this protocol improves specific labeling of delta receptors. Quantitative autoradiography showed that chronic dehydration causes no changes in mu receptor binding in the medulla oblongata of Long-Evans rats. However, there is increased delta receptor binding in the solitary, hypoglossal and gracilis nuclei, and the spinal nucleus of trigeminal system of dehydrated animals, suggesting that delta opiate receptors participate in the physiological response to dehydration.

Topics: Animals; Body Weight; Enkephalin, Leucine; Enkephalin, Leucine-2-Alanine; Feeding Behavior; Male; Medulla Oblongata; Rats; Rats, Inbred Strains; Receptors, Opioid; Receptors, Opioid, delta; Receptors, Opioid, mu; Time Factors; Urination; Water Deprivation