Synaptic Remodeling in the Dentate Gyrus, CA3, CA1, Subiculum, and Entorhinal Cortex of Mice: Effects of Deprived Rearing and Voluntary Running

Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus). We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus). We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils

A sorting system with automated gates permits individual operant experiments with mice from a social home cage

Winter Y, Schaefers ATU. A sorting system with automated gates permits individual operant experiments with mice from a social home cage. Journal of Neuroscience Methods. 2011;196(2):276-280.Behavioral experiments based on operant procedures can be time-consuming for small amounts of data. While individual testing and handling of animals can influence attention, emotion, and behavior, and interfere with experimental outcome, many operant protocols require individual testing. We developed an RFID-technology- and transponder-based sorting system that allows removing the human factor for longer-term experiments. Identity detectors and automated gates route mice individually from their social home cage to an adjacent operant compartment with 24/7 operation. CD1-mice learnt quickly to individually pass through the sorting system. At no time did more than a single mouse enter the operant compartment. After 3 days of adjusting to the sorting system, groups of 4 mice completed about 50 experimental trials per day in the operant compartment without experimenter intervention. The automated sorting system eliminates handling, isolation, and disturbance of the animals, eliminates experimenter-induced variability, saves experimenter time, and is financially economical. It makes possible a new approach for high-throughput experimentation, and is a viable tool for increasing quality and efficiency of many behavioral and neurobiological investigations. It can connect a social home cage, through individual sorting automation, to diverse setups including classical operant chambers, mazes, or arenas with video-based behavior classification. Such highly automated systems will permit efficient high-throughput screening even for transgenic animals with only subtle neurological or psychiatric symptoms where elaborate or longer-term protocols are required for behavioral diagnosis. (C) 2011 Elsevier BM. All rights reserved

Effect of postnatal methamphetamine trauma and adolescent methylphenidate treatment on adult hippocampal neurogenesis in gerbils

Schaefers AT, Teuchert-Noodt G, Bagorda F, Brummelte S. Effect of postnatal methamphetamine trauma and adolescent methylphenidate treatment on adult hippocampal neurogenesis in gerbils. European Journal of Pharmacology. 2009;616(1-3):86-90.Methyphenidate (e.g. Ritalin (R)) is the mostcommon drug used in the treatment of attention-deficit hyperactivity disorder. However, only a few studies have investigated the neuroanatomical long-term effects of this treatment. Prolonged application of methylphenidate during adolescence causes alterations in dopaminergic fiber or receptor densities in adult rodents. This study was conducted to investigate the effects of adolescent methylphenidate treatment on adult hippocampal neurogenesis in male gerbils (Meriones unguiculatus). Animals were first treated with either a single methamphetamine challenge on postnatal day 14 (to cause a disturbance in the dopaminergic system, to mimic the disturbed dopaminergic system seen in ADHD children) or saline and then received a daily oral application of 5 mg/kg methylphenidate or water from postnatal day 30-60 or were left undisturbed. On postnatal 90 gerbils were injected with bromodeoxyuridine (BrdU, a DNA synthesis marker) and sacrificed seven days later. Results reveal that the pretreatment with methamphetamine causes a decrease in the number of BrdU-positive cells in the dentate gyrus. Methylphenidate treatment however did not cause any differences in the number of labelled cells in any group. This implies that, despite methylphenidate's efficiency in inducing changes in the dopaminergic system and associated areas, it might be less effective in altering neurogenesis in the hippocampus. (C) 2009 Elsevier B.V. All rights reserved