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Biomedical subjects

H P von Hahn

Publications and source records attributed to H P von Hahn.

At least 19 recordsLinked to original sources
PubMed1986

Diurnal rhythms in neurotransmitter receptor binding and choline acetyltransferase activity: different patterns in two rat lines of Wistar origin.

Diurnal cycles for 8 ligand receptor pairs and choline acetyltransferase (ChAT) activity in 3 brain regions differed markedly in two rat lines, both of Wistar origin. Statistically significant differences between diurnal cycles in the two rat lines were found in the following parameters: 24 h means in 6 of 11 measurements, magnitude of cycle amplitudes, and phase position in 6 of 11 measurements, up to complete reversal of the acrophases in the case of ChAT activity in hippocampus. The importance of these findings--such major differences in two closely related rat lines--is obvious in any attempt to compare receptor-binding studies per se between laboratories using the same strain but not line, in studies of receptor rhythm characteristics, and in particular, for analysing the effects of brain-reactive drugs. While there are some reports on strain-dependency of cyclic functions, we are not aware that line-dependency has previously been described.

Animals↗
PubMed1985

Circadian variations of neurotransmitter binding in three age groups of rats.

Binding in 14 ligand membrane receptor pairs and choline acetyltransferase activity were studied at 4-hour intervals during a 24-hour cycle (12:12 light:dark). Cortex, hippocampus, cerebellum, striatum and brainstem were prepared from 3-, 12- and 24-month-old male rats. Cholinergic, alpha- and beta-adrenergic, dopaminergic, serotonergic, gabaergic and opiate binding were determined. In the aged animals, the times of the binding maxima are no longer locked to the same time of the light:dark cycle, and the cycle phases themselves are shifted in comparison to those of the young and adult group. Cycle amplitudes were smallest in the 12-month-old rats, increasing significantly in the 24-month group. The age changes in the overall (24-hour) means fall into 4 different patterns, none of which shows a linear age-related decrease. This points out the great importance of including an adult group (12 months) in all ageing studies on small mammals.

Aging↗
PubMed1984

Studies on neurotransmitter binding in senile dementia. Comparison of Alzheimer's and mixed vascular-Alzheimer's dementias.

Binding of 3H-labeled agonists and antagonists to muscarinic-cholinergic, alpha- and beta-adrenergic, dopaminergic, serotoninergic, and opiate receptors was studied in four regions of the neocortex and in hippocampus, thalamus, putamen, and caudatus in autoptic material from patients with senile dementia of Alzheimer type and of mixed vascular-Alzheimer pathogenesis. Different patterns of changes in ligand binding were found for the two groups. Some of these changes were quantitatively correlated with the histological scores of plaques and neurofibrillary tangles.

Aged↗
PubMed1978

Studies on the action of myelin basic protein (MBP) in rat brain.

The specificity of I125-MBP uptake and subcellular distribution on a discontinuous sucrose density gradient, compared to those of histone H 4 and cytochrome c, showed a high affinity of MBP for mitochondria and heavy synaptosomes, and of histone H 4 for lighter synaptosomes. One heavier synaptosomal subpopulation was almost equally labelled by both proteins. Cytochrome c showed only a low uptake into particular material. Receptor interaction studies of MBP with H3-labelled 5-hydroxytryptamine and naloxone gave negative results.

Animals↗
PubMed1978

[Trends in modern international gerontological research. Experimental aspects].

In a personal statement the author takes the view that gerontology and geriatrics deal with the same fundamental biological phenomenon, namely loss of adaptability and of the capacity to maintain the parameters of homeostasis. Two focal points of recent research in gerontology are cell cultures and the central nervous system. Work with cell cultures has so far been unexpectedly disappointing as far as basic understanding of the ageing process in vivo is concerned. Biochemical, morphological, physiological and pharmacological investigations into the ageing brain have on the other hand provided a wealth of new data which promise major insights into basic mechanisms of the ageing process. Aim of all gerontologocal research must be an "old age worth living" rather than a speculative search for a prolongation of lifespan.

Adaptation, Physiological↗
PubMed1977

Effect of multiple sclerosis serum on ventral root responses in isolated frog spinal cord.

Serum from patients with multiple sclerosis (MS) and other diseases was added to the medium perfusing isolated hemisected frog spinal cord, and the effect on ventral root responses (VRR) tested. As control, a standardized commercial human serum (Moni-trol I) was used. In 25 out of 40 spinal cord preparations Moni-trol gave inhibition of VRR ranging from 2.8 to 23.1%. 76% of the tests with confirmed MS sera showed inhibition of VRR, after deduction of the control serum effect, while 53% of the tests with sera from other diseases were inhibitory. Sera from cases of suspected but clinically unconfirmed MS gave strong inhibition (above 20%).

Animals↗
PubMed1976

Transport kinetics for the uptake of (3H)glycine and (3H)L-glutamate into dorsal and ventral slices of rat spinal cord.

The uptake of [3H]glycine and [3H]L-glutamate into slices of the dorsal and ventral halves of rat spinal cord taken from the thoracal (T3-9) and lumbar (L1-6) regions was determined in the concentration range 2 - 1 000muM. For both amino acids and in all four tissue pieces (thoracal dorsal and ventral, lumbar dorsal and ventral) biphasic linear regressions were obtained from the Lineweaver-Burk plots, demonstrating saturable transport mechanisms both in the high-affinity and in the low-affinity range. No significant dorsal-ventral or lumbar-thoracal differences were found for the transport constants Km of both amino acids. For the maximum velocity V similar dorsal-ventral and lumbar-thoracal gradients were found for both glycine and L-glutamate. These results, which are not entirely in agreement with the distribution of the endogenous pools of these amino acids, are critically discussed in view of the proposed function of high affinity uptake at the synapse.

Animals↗