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Biomedical subjects

A Raab

Publications and source records attributed to A Raab.

27 records · Page 2Linked to original sources
PubMed1982

Spontaneous activity of dorsal raphe neurons during defensive and offensive encounters in the tree-shrew.

The general characteristic of these telemetrically recorded neurons of dorsal raphe, such as firing rate under nembutal anesthesia, reaction to illumination changes or acoustic stimuli were comparable to those in the literature. The firing rate of the dorsal raphe neurons increased during defensive encounters (+51% +/- 29% S.D.;p less than 0.005) and defensive fights (+ 113% +/- 91% S.D.;p less than 0.02) as compared to the neuronal activity of the undisturbed resting animal. The fearful interaction of the animal with the experimenter led to the strongest increase in the firing rate (+187% +/- 114% S.D.; p less than 0.002) in all animals tested. The offensive animal showed decreased neuronal activity during offensive encounters (-21% +/- 13% S.D.; p less than 0.02) and offensive fights (-42% +/- 17% S.D.; p less than 0.05) as compared with the neuronal activity of the undisturbed resting animal. These findings indicate the crucial importance of the animals appraisal of the situational contest for the activity of dorsal raphe neurons.

Aggression↗
PubMed1982

A10 lesion and passive avoidance latency: correlation with limbic tyrosine-hydroxylase-activity.

Experiments were carried out with female tree-shrews (Tupaia belangeri). Following 6-hydroxydopamine injections into the ventral tegmental area, considerable variations in tyrosine-hydroxylase activity in the respective target regions of the A10 area occurred. Depletion of the THY-activity in the septum (SE), the entorhinal cortex (ECO), the frontal cortex and the basal ganglia correlated with an impairment in the performance of a passive avoidance task (indicated by testing 24 hours postshock). Partial correlation analysis revealed that the variations of THY-activity in the SE and ECO are primarily related to this failure in passive avoidance acquisition.

Animals↗
PubMed1981

Impact of social conflict between mice on testosterone binding in the central nervous system.

Adult male mice previously isolated for 14 days, were maintained in pairs as residents and intruders. They were categorized as dominant or subordinate on the basis of initiation of attacks and of wounding. After 10 days, the amount of free cytoplasmic testosterone receptors was determined in a part of the basal forebrain consisting of septum, diencephalon, corpus striatum, and amygdala. In addition, the plasma testosterone level and the activity of the adrenal tyrosine hydroxylase were measured. The adrenal tyrosine hydroxylase activity was increased in the dominant and the subordinate mice compared to isolated controls. Subordinates had higher tyrosine hydroxylase activities than dominants. The specific testosterone in brain cytosol of dominants were freed like those of 6-day castrates despite the fact that the plasma testosterone concentration of dominants (717 ng/100 ml) was not significantly decreased compared to controls (1,003 ng/100 ml). In subordinates, the plasma testosterone content fell to 265 ng/100 ml while castrated mice showed 20-43 ng/100 ml. The amount of free testosterone specific binding sites in the brain cytosol of subordinates corresponded to that of 10-day castrates. Thus, the amount of circulating total testosterone does not seem to be the only factor determining the binding of available testosterone in brain cytosol.

Aggression↗
PubMedDate not supplied

Continuous social defeat induces an increase of endogenous opioids in discrete brain areas of the mongolian gerbil.

Dyads of a victor and a loser of mongolian gerbils (Meriones unguiculatus) coexisted for seven days; isolated animals served as a further experimental group. beta-Endorphin, Met-enkephalin and dynorphin were measured in several brain areas and in the anterior and neurointermediate pituitary. beta-Endorphin and Met-enkephalin were increased in the amygdala of defeated as compared to victorious animals. Met-enkephalin in the hypothalamus and in the striatum were lower in isolated than in coexisting gerbils. Coexistence decreased beta-endorphin in the amygdala and in the hypothalamus as compared to isolation. The results provide biochemical evidence for the role of central endogenous opioid-peptide systems in the physiology of victory and defeat. Dynorphin showed no variation with social conflict and social status.

Adrenal Glands↗
PubMedDate not supplied

Gonadal response to psychosocial stress in male tree shrews (Tupaia belangeri) morphometry of testis, epididymis and prostate.

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

[Anxiolytic efficacy and tolerance of tetrabamate in anxious patients abusing alcohol. Multicenter double-blind versus placebo study].

The anxiolytic efficacy of tetrabamate was evaluated in 68 out-patients presenting an anxiety state with alcohol abuse according to DSM III criteria. The study followed a double-blind placebo-controlled design with parallel groups and lasted for 21 days. Anxiety was evaluated by the Hamilton anxiety scale, Norris visual analog scales, and the Hopkins Symptom Check List, along with the investigator's assessment. Safety was evaluated in terms of somatic symptoms (CHESS 84) and the physician's overall evaluation. The anxiolytic activity of tetrabamate (three 300 mg tablets/day) was significantly greater than that of placebo from seventh day on. There were no statistically significant differences in safety profile between tetrabamate and placebo. Moreover, in the tetrabamate group the significantly greater improvement in the scores of somatic symptoms indicates that the compound caused no notable adverse effects and its activity on somatic complaints (psychopathologic and/or toxic).

Alcoholism↗