ATD-induced reduction in somatodendritic 5-HT(1A) autoreceptor binding may represent an intrinsic 'homeostatic response' reducing serotonergic feedback in dorsal raphe projection areas. In contrast, the increase in 5-HT(2A) receptor after CTD may be a compensatory response to a long-term reduction in 5-HT.

No abstract

Aims:  To determine whether Clostridium botulinum neurotoxin (BoNT) production in anaerobic culture was affected by temperature and could influence the sandwich ELISA (sELISA) detection of group III toxins in pre‐enriched gastrointestinal (GI) contents from clinically suspect cattle botulism cases. Methods and Results:  Bovine post‐mortem GI samples taken from 124 and 96 animals with suspect and nonsuspect botulism, respectively, were pre‐enriched anaerobically at 30 and 37°C prior to testing by sELISA. After enrichment at 37°C, BoNT was demonstrated in all clinically suspect bovine botulism cases that had been identified by the mouse bioassay, and enrichment by both temperatures enabled BoNT detection in a number of mouse bioassay–negative suspect cases. Conclusions:  Culture temperature does influence the production of group III BoNT, and incubation at both 30 and 37°C is required for optimum detection. Significance and Impact of the Study:  The in vitro assay defined in this study has the potential of improving the confirmation rate of clinically suspect cattle botulism cases whilst reducing the use of the costly and ethically sensitive mouse bioassay, the current diagnostic gold standard for BoNT testing.

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The current study examined behavioral and histological effects of amyloid-β (Aβ) protein precursor (AβPP) overexpression in transgenic (Tg) rats created using the same gene, mutation, and promoter as the Tg2576 mouse model of Alzheimer's disease (AD). Male Tg+ rats were bred with female wild-type rats to generate litters of hemizygous Tg+ and Tg- offspring. Tg+ rats and Tg- littermates were tested for memory deficits at 4, 8, and 12 months old using a water-maze procedure. There were no significant behavioral differences between Tg+ rats and Tg- littermates at 4 months old but there were significant differences at 8 and 12 months old, and in probe trials at 8 and 12 months old, the Tg+ rats spent significantly less time and covered less distance in the platform zone. Under acquisition of a fixed-consecutive number schedule at 3 months old, Tg- littermates demonstrated a longer latency to learning the response rule than Tg+ rats; while this might seem paradoxical, it is consistent with the role of overexpression of AβPP in learning. Histological analyses revealed activated astrocytes in brains of Tg+ rats but not Tg- littermates at 6 months old, and thioflavin-S positive staining in the hippocampus and cortex of 17-month old Tg+ rats but not Tg- littermates. Quantification of Aβ load in the brain at 22 months indicated high levels of Aβ38, Aβ40, and Aβ42 in the Tg+ rats. These data suggest this model might provide a valuable resource for AD research.