Influence of acute and chronic administrations of beta-casomorphins on the maternal motivation in albino rats

The influence of food-derived opioid peptides beta-casomorphines on the manifestation of nursing albino rats maternal behavior was investigated. It was shown that both acute and chronic (during the postnatal period) administration of beta-casomorphin-7 (Tyr-Pro-Phe-Pro-Gly-Pro), the typical representative of this group of peptides, decreases the level of the parental motivation. The effects of beta-casomorphin-7 were naloxone-dependent; N-terminal-reduced analogues had a significantly lesser activity. The obtained results testify in favor of the probable role of casein opioid fragments which were formed in mammary glands of a nursing female, in the development of maternal behavior abnormalities. At the same time, beta-casomorphins could be considered as the limiting factors to the excessive manifestation of the parental motivation.     

The role of dopamine and opioid systems in the regulation of maternal behavior

This review describes in detail the different components and neuroanatomical basis of maternal behavior and also methodological approaches to investigation of parental reactions. The contributions of some endocrinal and neuromediator brain systems (in the first place, opioid and dopaminergic) to the regulation of maternal behavior are reported. The influences of ligands of opioid and dopamine receptors on the expressions of paternal reactions are analyzed especially. In concluding part the reasons of maternal depression and possibilities of this malfunction pharmacological correstion are discussed.     

The distribution of insulin-containing cells in the developing tissues of the common frog (Rana temporaria)

Monoclonal antibodies to pig insulin were used to follow the changes in localization of insulin-containing cells during the ontogenesis of the brown frog, Rana temporaria L., from stage 20 (Dabagian, Sleptsova, 1975) until completion of metamorphosis and beginning of active nutrition. Insulin-containing were localized in brain, surface epithelium, intestine, olfactory epithelium, taste teats, kidney tubules, ciliated epithelium of the oral cavity, pancreas, Jacobson and interjaw glands was found out. Localization of insulin-containing cells and type of their specific fluorescence varied at different stages of development. Formation of the insulin-containing system of amphibians on the whole is typical for the development of diffuse endocrine system in vertebrates.