Male tree shrews (46 animals in all) were kept under distinct social conditions. Two kinds of controls were investigated: isolated animals as well as males out of female/male couples. Comparing these two groups only little isolation effect was observed. With the other individuals, initially isolated, dyads were formed which coexisted for 7 or 50 days. In a third group of dyads, after 50 days of coexistence social circumstances were aggravated for 5 more days by providing only half of the cage. All dyads established clear cut dominance relationship. Animals behaving dominantly developed no signs of gonadal regression rather that of stimulation concerning especially with the epididymis. In contrast, animals behaving as subordinates revealed profound regressive changes although differentiated with respect to any parameter, both morphological and conditional. In testis, chronical subordination (50 days, mainly 50 + 5 days) leads to a loss of organ weight, narrowing of seminiferous tubules and to enlarged spermatogonia nuclei. The case is similar in the epididymis: loss of organ weight, lowered epithelium and an enormously increased frequency of immature germ cells within tail segments. Whereas prostate weight drops continuously, striking histological regression occurs already after 7 days (extreme diminution of epithelial height and of epithelial cell nuclei).

Animals↗

PubMedDate not supplied

The influence of social isolation on ethanol preference behavior and dopamine release in telencephalon slices in mice.

We examined the relation between the duration of social isolation and alterations in ethanol preference behavior and the dopamine release in telencephalon slices in mice. Ethanol preference developed only after an isolation period of 2 weeks and a further ethanol treatment of 2 weeks. It did not appear after an isolation period of 6 weeks, in mice without ethanol treatment, and in group-housed mice. The dopamine release was lowered in mice isolated for 2 weeks and is normalized in combination with ethanol treatment. The dopamine release inhibition evoked by social isolation of 2 weeks probably reflects a functional state with high sensitivity for induction of an ethanol preference behaviour.

Animals↗

PubMedDate not supplied

[Content, release and absorption of biogenic amines in CNS structures of the rat under the influence of sultones (proceedings)].

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Absorption↗

PubMedDate not supplied

Some aspects on the relationship between lipids, neurotransmitters, and aging.

A relationship is discussed between free radicals, lipid metabolism, neurotransmitters, and aging. Almost all of the lipid fractions of nerve tissue are heavily exposed during aging to the deleterious effects of a continuous formation of free radicals. In comparative terms, brain tissue has less enzymatic capacity to lower or counteract the rate of lipid peroxidation. However, various defense mechanisms exist that enable phospholipid reconstitution to occur and their metabolic activity to be maintained through reutilization of products arising from their biosynthesis and turnover. The effect of hyperoxygenation or hypoxygenation in association with free radicals generation on neurone stability and neurotransmitters reveals different susceptibilities to neuronal stimuli- and release quotients related to aging. With respect to the relationship between the environment and aging, neurotransmitter mechanisms, exemplified by that of dopamine and its turnover, play an important role in coping with stress, iatrogenic and toxic factors during aging. Possible pharmacological and other ways of mitigating age-related changes by means of protective reactions, accelerated repair processes, and compensatory mechanisms are discussed.

Aged↗