Biomedical subjects

H Schicknick

Publications and source records attributed to H Schicknick.

5 recordsLinked to original sources

PubMed1994

Sequence-specific impairment of learning by c-jun antisense oligonucleotides.

Hybridization studies revealed a differential accumulation of c-jun and jun B mRNA in the hippocampus and cerebral cortex of rats trained on a foot-shock-motivated brightness discrimination. Supposing that early gene expression is functionally significant for plastic changes in the brain, we used antisense phosphorothioate oligodeoxynucleotides (S-ODN) in vivo to study effects of specific inhibition of c-jun and jun B gene expression on learning and memory formation in rat brain. Discrimination performance of rats was impaired after intrahippocampal injection of anti-c-jun S-ODN but not of anti-jun B S-ODN. These results imply that topically injected antisense oligonucleotides affect processes involved in learning and memory in a sequence-specific manner.

Animals↗

PubMed1993

Genetic analysis of isolation-induced aggression in the mouse. III. Classical cross-breeding analysis of differences between two closely related inbred strains.

In two preceding papers we reported on two closely related inbred mouse strains, ABG and AB@Halle that display very large differences in isolation-induced intermale aggression. In the present article we investigated animals from a complete Mendelian cross between these strains to test the hypothesis that the behavioral difference is due to genetic variation at only a few loci, possibly only one. In the quantitative-genetic analysis of generation means and variances for the behavioral variables analyzed, relatively simple models were found. As epistasis was present in some cases, the monogenic hypothesis could not be confirmed. Also, the analysis of the segregating generations by means of Collins' nonparametric method revealed significant deviations of observed from expected distributions. We conclude that differences at more than only one single locus are correlated with the behavioral difference.

Aggression↗

PubMed1992

Hippocampal mossy fiber distribution does not correlate with two-way active avoidance performance in backcross lines derived from inbred mouse strains DBA/2 and C3H.

To elucidate the relation of genetically induced variations in two-way active avoidance performance and the extent of the hippocampal infra/intrapyramidal mossy fiber system (IIP-Mf) in inbred mouse strains DBA/2 (high performance, small IIP-Mf) and C3H (low performance, large IIP-Mf) we investigated a backcross line containing the DBA/2-derived genetic determinants for high avoidance performance in a C3H background. In the seventh backcross generation variations in performance analogous to the original strains were observed whereas the extent of mossy fibers was nearly homogeneous. This result suggests that both variables are determined by separate genetic factors at least in these strains and that differences in mossy fiber distribution are not an essential prerequisite for different active avoidance performance.

Afferent Pathways↗

PubMed1992

Genetic analysis of isolation-induced aggression. I. Comparison between closely related inbred mouse strains.

Young adult males of the inbred mouse strains BALB/c, C57BL/6, CBA, C3H/He, and the outbred strain NMRI showed significant interstrain differences for isolation-induced aggression as measured in a standard-opponent test. Additionally, four related inbred strains of common origin (ABG, AB//Halle, ABB, AB//Jena) were studied. ABG and AB//Halle showed nearly no overlap for the trait isolation-induced aggression. Tests of histocompatibility and coat color, as well as mandible measurements, confirmed a close genetic relationship between ABG and AB//Halle. The large difference for isolation-induced aggression between these two closely related strains offers excellent opportunities to search for single gene correlates of aggression.

Aggression↗

PubMedDate not supplied

Suppression of c-fos induction in rat brain impairs retention of a brightness discrimination reaction.

Recently, the induction of transcription factor-encoding immediate-early genes such as c-fos was observed in distinct brain regions of rats trained to acquire a footshock-motivated brightness discrimination in a Y-maze. The functional relevance of inducible transcription factors for learning and memory formation is, however, not clear. To address this question in the present study, we have used a synthetic antisense phosphorothioate oligodeoxynucleotide to suppress in vivo the expression of c-fos in rat brain. Intrahippocampal application of the oligodeoxynucleotide 10 hr and 2 hr before starting a brightness discrimination training drastically reduced the induction of c-Fos immunoreactivity normally observed in limbic and cortical areas after the training session. Acquisition of the discrimination reaction was not affected by this treatment. In a relearning test 24 hr after the first training, retention of the discrimination reaction was specifically impaired compared with rats pretreated with control oligodeoxynucleotide or saline. Our findings are consistent with the hypothesis that the inducible transcription factor c-Fos is involved in processes underlying the formation of long-term memory.

Animals↗