Biomedical subjects

S Kerbusch

Publications and source records attributed to S Kerbusch.

5 recordsLinked to original sources

PubMed1992

Effects of chronic dietary choline on temporal discrimination of BN and WAG rats.

Using rats of the inbred BN and WAG strain, we tested the hypothesis that chronic dietary choline supplementation would especially affect the timing behavior of BN rats because of their lower cholinergic activity and their poor performance in aversively motivated learning and memory tasks. An apparent effect of chronic choline supplementation (2.5 mg choline chloride per ml water) on DRL-8" responding was not confirmed in a second experiment when the choline concentration was doubled. WAG rats treated chronically with choline showed a poorer temporal discrimination performance on a DRL-16" schedule than untreated WAG rats. In contrast, choline supplementation never had an effect on the performance of BN rats. The results of the DRL-16" experiment provide partial support for a hypothesis proposed by Church and Meck that the remembered time of reinforcement is inversely related to the functional activity of brain cholinergic activity: acetylcholine precursor treatment increases memory storage speed, which results in an overestimation of the time elapsed. An alternative explanation, which takes into account the aberrant EEG activities of WAG rats, is also discussed.

Acetylcholine↗

PubMed1992

Chronic dietary choline enrichment affects DRL responding of old, but not of adult CPBB rats.

Using adult (11-month-old) and aged (22-month-old) inbred female CPBB rats, we tested the hypothesis that chronic dietary choline supplementation affects timing behavior. The rats had received choline chloride in their tap water for about 9 months before they acquired responding on a differential reinforcement of low-rate schedule with a critical delay of 8 s (DRL-8"). One retention session and two extinction sessions were given 4 weeks after the end of acquisition. The treatment had no effect on the timing behavior of the adult rats. Choline-treated old animals made more perservation errors, i.e., responses with interresponse times (IRTs) < 2 s, than the untreated old control rats. Even after correction for burst responses, the frequency of short IRTs was higher in the treated than in the control group, indicating that choline supplementation slightly impaired timing behavior. The mechanisms underlying the action of supplemented choline are still unknown.

Aging↗

PubMed1990

Genetic correlations in validating emotionality.

Sixty-six rats of seven inbred strains were observed in an open field (OF) and in a light-dark preference box (LDB). Each set of apparatus provides measures of locomotor activity and of the time spent in the "most protected" area (the corners in the OF, the dark compartment in the LDB). These measures are proposed to be indices of emotionality. In the present study, the reliability and validity of the OF and LDB measures were determined by genetic correlations. Genetic correlations (rGEN) within and between tests were used as they provide a more coherent picture of reliability and validity of the measures than product-moment correlations (rPM), since rGEN's are appropriate estimates of "true" individual scores. It appeared that the activity measure in the OF and the occupancies of the most protected parts of OF and LDB were valid indices of emotionality, while the activity measure in the LDB was not. We recommend that the occupancy measures in the OF and the LDB should be used in addition to the commonly used activity measure in the OF to assess emotionality. The results indicate that genetic correlations provide a useful tool to validate measures in animal research. The only experimental manipulation in this approach consists of using the variation between inbred strains.

Animals↗

PubMed1982

Synaptosomal uptake studies on recombinant inbred mice; neurotransmitter interaction and behavioral correlates.

The uptake of noradrenaline, choline and GABA into whole brain synaptosomes from the mice inbred strains C57BL/6By, BALB/cBy, their reciprocal crosses and seven recombinant inbred strains derived from the F2 crosses was measured in order to study the relation between different neurotransmitter systems and their possible correlations with behavioral parameters. Analysis of variance demonstrated significant differences in both Vmax and Km for each substrate between the inbred strains studied. Only the Km for GABA uptake did not reach significance although a strong trend (P = 0.07) was apparent. For none of the uptake parameters clear strain distribution patterns were found. A positive phenotypic as well as genotypic correlation was found between the Vmax and Km for noradrenaline, choline and GABA uptake. A genetic analysis showed a positive correlation between the Vmax for noradrenaline and choline uptake. Since prior to these neurochemical studies, all subjects were tested in a variety of behavioral paradigms, phenotypic and genotypic correlations between behavioral and neurochemical parameters could be calculated. The most consistent correlations were found between noradrenaline and choline uptake and water consumption and the preference ratio as measured in a conditioned taste aversion test.

Animals↗

PubMed1982

Analysis of behavioural responses to an ACTH analog in CXB/By recombinant inbred mice.

Male mice of the C57BL/6By and BALB/cBy inbred strains, their reciprocal F1 hybrids, and 7 recombinant inbred strains, were tested for open-field activity, a shock-motivated successive reversal position discrimination problem in a T-maze, and a toggle box exploration task. The test battery was repeated one month later. Finally, mice were tested for the acquisition and extinction of a taste aversion conditioned by ethanol injection. Mice of each strain were tested after injection with saline or one of 3 doses of an ACTH analogue. Highly significant genotypic differences were found for all measures, an expected result. The strain distribution pattern seen in the toggle box suggested single gene mediation of exploratory activity after habituation. One aspect of avoidance responding and extinction of conditioned taste aversion also yielded strain distribution pattern consistent with single gene control. Peptide treatment reduced internal field crossings in the open field. This effect was not strain dependent. Peptide treatment had no effect on T-maze learning, conditioned taste aversion, or toggle-box exploration.

Adrenocorticotropic Hormone↗