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Biomedical subjects

H Feer

Publications and source records attributed to H Feer.

At least 37 records · Page 2Linked to original sources
PubMed1984

Hypothalamic alpha 2- and beta-adrenoceptor rhythms are correlated with circadian feeding: evidence from chronic methamphetamine treatment and withdrawal.

The circadian regulation of food intake in rats is correlated with a bimodal rhythm of beta-adrenoceptor binding in the lateral hypothalamus and a unimodal rhythm of alpha 2-adrenoceptor binding in the medial hypothalamus. Chronic methamphetamine treatment provides evidence for a functional correlation: beta-adrenoceptor binding in the lateral hypothalamus is reduced at dusk, together with reduction of food intake; alpha 2-adrenoceptor binding in the medial hypothalamus is increased at dawn, together with persistent food intake. Long-term changes in these two adrenergic systems are also correlated with homeostasis of food intake: 24-h mean beta-adrenoceptor binding is reduced and alpha 2-adrenoceptor binding is increased upon methamphetamine withdrawal, when rebound feeding occurs. Corticosterone, although normally coupled to adrenergic mechanisms that regulate feeding, is phase delayed after chronic methamphetamine treatment.

Animals↗
PubMed1984

3H-imipramine and 3H-cyano-imipramine binding in rat brain tissue: effect of long-term antidepressant administration.

3H-imipramine and 3H-cyano-imipramine binding was determined in brain homogenates of rats which had been treated for 21 days with imipramine or desimipramine. When compared to control animals, long-term administration of these antidepressants did not induce any alteration in the maximal number of 3H-imipramine or 3H-cyano-imipramine binding sites. However, a transient increase in the apparent dissociation constant was observed. Such findings are discussed in respect to previous studies, which have been highly contraversial.

Animals↗
PubMed1983

Individually housed rats exceed group-housed animals in rotational movements when exposed to a novel environment.

Individually and group-housed rats of both sexes were compared in respect to spontaneous rotational movements when exposed to a novel environment. Thereby, individually housed animals showed a higher number of rotational movements than group-housed controls. During an L12:D12 cycle, such movements occurred most frequently at the beginning of the dark phase, when locomotor activity was highest. It is assumed that these rotations are part of the hyperreactivity toward a novel environment induced by long-term individual housing.

Animals↗
PubMed1983

Regional distribution of [3H]imipramine binding sites in the CNS of Roman high and low avoidance rats.

The high affinity binding of [3H]imipramine to membranes was compared in 7 brain regions from two psychogenetically selected rat lines (RHA/Verh, RLA/Verh). A significantly higher binding in RHA/Verh rats, as compared to RLA/Verh rats, was found in cortex and striatum. All other regions, except hypothalamus, showed a trend in the same direction (RHA/Verh greater than RLA/Verh). In the hypothalamus, however, [3H]imipramine binding for RLA/Verh rats significantly exceeded that found in RHA/Verh animals.

Animals↗
PubMed1983

Adrenoceptor changes in spontaneous hypertensive rats: a circadian approach.

Circadian adrenoceptor rhythms were measured in the cortex, hypothalamus, cerebellum and pons-medulla of WKY and SHR rats. The 24-h mean binding to alpha 1-, and beta-adrenoceptors was higher in SHR than WKY in all regions:greatest differences were found at the end of the dark phase. The most consistent and large amplitude circadian rhythms in adrenoceptor binding occurred in the hypothalamus; strain differences in wave form of the rhythm were the most noticeable phenomenon. In the pons-medulla SHR rats showed decreased rhythm amplitudes. In the cerebellum, beta-adrenoceptor binding was higher in SHR rats at all time points, with an identical rhythm to that in WKY rats. Thus regional differences between SHR and WKY rats were expressed in changes in many circadian rhythm parameters. There were no differences between SHR and WKY in the ratios of pre-synaptic: post-synaptic receptors. High affinity binding to alpha-adrenoceptors showed similar circadian rhythms to total specific binding, indicating that the short-term fluctuations cannot be attributed to change in affinity state. Whether these modifications in circadian rhythm characteristics are related to the development or maintenance of hypertension in the SHR strain remains to be investigated.

Adrenergic alpha-Antagonists↗
PubMed1983

Circadian rhythm of [3H]imipramine binding in the rat suprachiasmatic nuclei.

High affinity imipramine binding undergoes circadian variations of ca. 35% amplitude in many rat brain nuclei. The suprachiasmatic nuclei of the anterior hypothalamus (considered to be the circadian pacemaker driving many overt rhythms) has highest imipramine binding at the end of the dark and lowest at the end of the light phase. A similar circadian rhythm has previously been observed for serotonin uptake in the suprachiasmatic nuclei. In conjunction with other findings, these data indicate that serotonergic turnover in the suprachiasmatic nuclei decreases at lights on and increases at lights off.

Animals↗
PubMed1983

Spontaneous hypertensive rats: behavioral and corticosterone response depend on circadian phase.

Baseline and reactive motor activity and corticosterone levels of spontaneous hypertensive rats (SHR) and their normotensive controls (WKY) were compared with respect to circadian rhythmicity. In the open field, SHR showed higher ambulation and rearing and less defecation than WKY in both light and dark phases. There were significant interactions between strain and time of day in the rate of habituation. SHR showed elevated baseline motor activity, increased motor response and enhanced corticosterone response to "mild" stress only in the light phase. There may be a disorder of temporal organisation in SHR characterised by increased sensitivity to external stimuli during the sleeping state.

Animals↗
PubMed1983

[The biology of depression].

There are several arguments in favor of a biological cause of endogenous depressions coming from clinical experience, genetic studies and the pharmacology of antidepressants. Impaired impulse transmission across the synapses of noradrenergic and serotoninergic systems has been for 20 years considered to be the underlying defect. In contrast to earlier theories this defect consists more probably in an altered sensitivity of post-synaptic receptors than in reduced concentration of the amines. As neurotransmission is regulated in a complex way the interpretation of experimental results is often ambiguous. The noradrenergic medial forebrain bundle, part of the reward system, is of special importance for a biological theory of depression.

Antidepressive Agents↗
PubMed1982

Behavioural comparisons between individually- and group-housed male rats: effects of novel environments and diurnal rhythm.

Individually-housed rats, when compared with group-housed controls, have been previously shown to be hyper-reactive when exposed to an openfield at the beginning of the dark-phase; this was not due to elevated spontaneous activity. In the present experiments locomotor and rearing activities were determined immediately after exposing animals to a novel environment, and after 6 and 24 h of habituation to the test-environment. Additionally, after 24 h of adaptation, animals' responses towards a modification of the test-environment were examined. Four parallel experiments were carried out, each starting at a different time in the light/dark cycle. Individually-housed rats were hyper-reactive in novel environments and showed a slower habituation at all time points tested. Part of behavioural parameters show clearcut day/night variations, but differences between individually- and group-housed rats do not seem to be influenced by the time of day.

Animals↗
PubMed1982

Different reaction patterns in individually and socially reared rats during exposures to novel environments.

Individually and group-reared male rats were behaviourally compared after various periods of different housing, (i) during a first exposure to the new environment, and (ii) after habituation (two repetition trials) to the situation, during a fourth exposure in a slightly modified test-box. Compared to group-housed controls an elevated locomotor activity upon the first exposure and a reduced reaction in response to the slight modifications were found in individually housed rats.

Aging↗
PubMed1981

3H-Diazepam binding sites in Roman high- and low-avoidance rats.

The binding of 3H-diazepam to membrane benzodiazepine receptors was examined in 2 psychogenetically selected lines of rats, which differ according to the selection criterion in avoidance behaviour (RHA/Verh greater than RLA/Verh) and, in addition, in emotionality (RHA/Verh less than RLA/Verh). RHA/Verh rats tended to show higher specific diazepam binding in all CNS-subregions when compared with RLA/Verh animals. Significant differences were found in the cortex, striatum, hippocampus, thalamic region and pons-medulla. These results reinforce the contention that a system involving benzodiazepine receptors may play a role in emotional behaviour.

Animals↗
PubMed1981

Individually reared rats: alteration in noradrenergic brain functions.

The influence of social isolation in rats on postsynaptic alpha 1- and beta-adrenergic receptors, on the cAMP generating system and on the presynaptic uptake mechanism in the central noradrenergic system was examined in different brain regions. Rearing rats in isolation from the 19th day of life for 12 weeks leads in all regions to a general tendency for a reduction in 3H-DHA binding, to an enhanced 3H-WB4101 binding and to a decreased responsiveness of the noradrenaline sensitive cAMP generating system. These changes reach significant only in the pons-medulla-thalamus region. Isolated rats showed an increased synaptosomal uptake of noradrenaline, most pronounced and significant in the hypothalamus. Our data provide further support for a disturbance in central noradrenergic function in isolated rats.

Adenylyl Cyclases↗
PubMed1980

In vivo 3H-d-LSD binding in small punched out rat brain regions.

We have developed an in vivo 3H-d-LSD-binding method in the rat brain to measure the 3H-d-LSD concentration in specific brain regions and nuclei. In the cortex, d-LSD binding sites increase from the occipital to the frontal part without a change in their affinity. Compared to the hippocampus, striatum, cortex and raphe nuclei, the substantia nigra contains a d-LSD binding site of lower affinity.

Animals↗
PubMed1979

[Nonverbal communication and its implication for psychiatry].

Psychiatry unlike philosophy (with its problem of solipsism) recognizes the existence of other minds from the nonverbal communication between doctor and patient. This nonverbal, or having deeper roots in evolution, preverbal communication, is the connection within a herd or horde. As psychiatry gains many of its diagnostic criteria like mood, excitation or fear by nonverbal communication, it brings the patient in a biological-ethological frame where aim, biological sense and evolutional origin are justified questions of normal and abnormal behavior and of psychological events.

Animals↗