Enhancement of Aggression Induced by Isolation Rearing is Associated with a Lack of Central Serotonin / 神经科学通报·英文版

Isolation rearing (IR) enhances aggressive behavior, and the central serotonin (5-hydroxytryptamine, 5-HT) system has been linked to IR-induced aggression. However, whether the alteration of central serotonin is the cause or consequence of enhanced aggression is still unknown. In the present study, using mice deficient in central serotonin Tph2 and Lmx1b, we examined the association between central serotonin and aggression with or without social isolation. We demonstrated that central serotonergic neurons are critical for the enhanced aggression after IR. 5-HT depletion in wild-type mice increased aggression. On the other hand, application of 5-HT in Lmx1b mice inhibited the enhancement of aggression under social isolation conditions. Dopamine was downregulated in Lmx1b mice. Similar to 5-HT, L-DOPA decreased aggression in Lmx1b mice. Our results link the serotoninergic system directly to aggression and this may have clinical implications for aggression-related human conditions.

Study on the physical growth status of birthweight discordant twins under 4 years old / 中国实用儿科杂志

OBJECTIVE: To study the physical growth characteristics of birthweight discordant twins(BDT)under 4 years old. METHODS: The physical growth characteristics of BDT under 4 years old born from September 2010 to December 2017 in child health care system of Children's Hospital of Chongqing Medical University were analyzed retrospectively. R 3.5.3 was used to clean up the database,analyze the distribution of different degree of birthweight discordance,and draw the fitting curves. More than 20% of birth weight difference was taken as inclusive criteria of BDT. BDT were divided into preterm or full-term groups,and low birthweight or normal birthweight groups respectively. SPSS 19.0 software was used for statistical analysis. RESULTS: A total of 141 pairs of BDT were included,accounting for 15.4%(141/916). The degree of birthweight difference in premature BDT was higher than that of full-term BDT(t=3.820,P<0.001). The growth discordance of preterm BDT lasted longer. Physical growth of low/very low birthweight BDT was slower than that of normal birthweight BDT under 4 years old. The growth status of BDT didn't reach the average level of WHO growth chart by the time of the last follow-up. CONCLUSION: Birthweight discordance of twins could have longlasting effects on further growth and development. Preterm twins have higher degree of birthweight discordance,and the growth discordance lasts longer. Low birthweight is an important reason for growth retardation of the lighter BDT.Growth of BDT should be monitored regularly to increase follow-up compliance.

Expression and Significance of HIF-1α in Erythropoiesis of Secondary Iron Overload Disease after Irradiation Damage / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To study the expression of hypoxia inducible factor 1α(HIF-1α) of iron-overloaded in irradiated mice and its effect on erythropoiesis.</p><p><b>METHODS</b>Twenty mice were randomly divided into 4 groups: Ctrl (control group), IR (irradiation group), IO (irradiation + iron overload group), and RAPA (rapamycin treatment group). The iron overload model was verified. The CFU-E (colony forming unit-erythroid) and BFU-E(burst colony forming unit-erythroid) were cultured; flow cytometry was used to detect the ratios of early stage (Ter119CD71) to late stage (Ter119CD71) of primitive erythroblasts; RT-PCR was used to detect the mRNA expression of HIF-1α and its related signal molecules in bone marrow cells.</p><p><b>RESULTS</b>The expression of HIF-1α in IR and IO group was significantly higher than that in Ctrl group, and that in IO group was significantly higher than IR group (P<0.05). The ratio of late stage primitive erythroblasts, the number of CFU-E and BFU-E in both IR and IO group were lower than those in Ctrl group, and those in IO group were significantly lower than those in IR group (P<0.05). Compared with Ctrl group, the expression of HIF-1α related signal pathway molecules in both IR and IO group was significantly decreased (P<0.05). Compared with IO group, the expression of HIF-1α and its related signal molecules in RAPA(mTOR inhibitor) group was decreased significantly (P<0.05), the number of BFU-E was increased significantly(P<0.05).</p><p><b>CONCLUSION</b>Irradiation induces the increase of HIF-1α and the decrease of the ability of hematopoietic colony formation and the ratio of late stage primitive erythroblasts. Iron overload can aggravate the injury. mTOR inhibitor rapamycin can partially alleviate the injury, suggesting that iron overload can lead to injury of erythropoiesis through HIF-1α.</p>

Parkin promotes proteasomal degradation of p62: implication of selective vulnerability of neuronal cells in the pathogenesis of Parkinson's disease

Mutations or inactivation of parkin, an E3 ubiquitin ligase, are associated with familial form or sporadic Parkinson's disease (PD), respectively, which manifested with the selective vulnerability of neuronal cells in substantia nigra (SN) and striatum (STR) regions. However, the underlying molecular mechanism linking parkin with the etiology of PD remains elusive. Here we report that p62, a critical regulator for protein quality control, inclusion body formation, selective autophagy and diverse signaling pathways, is a new substrate of parkin. P62 levels were increased in the SN and STR regions, but not in other brain regions in parkin knockout mice. Parkin directly interacts with and ubiquitinates p62 at the K13 to promote proteasomal degradation of p62 even in the absence of ATG5. Pathogenic mutations, knockdown of parkin or mutation of p62 at K13 prevented the degradation of p62. We further showed that parkin deficiency mice have pronounced loss of tyrosine hydroxylase positive neurons and have worse performance in motor test when treated with 6-hydroxydopamine hydrochloride in aged mice. These results suggest that, in addition to their critical role in regulating autophagy, p62 are subjected to parkin mediated proteasomal degradation and implicate that the dysregulation of parkin/p62 axis may involve in the selective vulnerability of neuronal cells during the onset of PD pathogenesis.

Intracellular recordings and multi-parameter analysis of long-term potentiation of synaptic responses in chick brain slices / 生理学报

Day-old chick is unique animal model in brain development and behavior study. The intermediate medial mesopallium (IMM), a region of the chick forebrain, is intimately involved in the early learning processes, which offers the ideal opportunity to study the neural changes that underlie behavioral plasticity. In this paper, the intracellular recordings were conducted from IMM neurons in chick forebrain slices, in which electrophysiological properties, synaptic responses and long-term potentiation (LTP) were observed. Coronal sections of left forebrains (500 mum thick), containing IMM, were prepared from domestic chicks, aged 2-10 days. In 69 IMM neurons, the resting membrane potential was measured to be (-59.4+/-5.3) mV, slope membrane resistance (70.8+/-27.2) MΩ, and time constant (10.2+/-4.3) ms. The amplitude, threshold, overshoot, half-width, max rise slope and max decay slope of action potential evoked by intracellular current injection were (85.2+/-9.4) mV, (-38.7+/-7.6) mV, (25.6+/-8.9) mV, (2.1+/-0.5) ms, (150.5+/-41.2) mV/ms and (-64.3+/-14.0) mV/ms, respectively. Spike-firing frequency was increased with depolarizing current intensity in 32 of 69 tested cells [linear regression slope was (21.5+/-10.9) Hz/nA, P<0.05 in all cells]. The depolarizing synaptic responses (i.e. EPSPs), with stimulus intensity- and membrane potential-dependent properties, were elicited by dorsal (n=25) or ventral (n=62) focal electrical stimuli at 0.1 Hz in all tested IMM neurons and could be nullified reversibly by perfusion with 100 mumol/L AP5 (NMDA receptor antagonist) and 3 mumol/L DNQX (non-NMDA receptor antagonist), but enlarged by 6 mumol/L bicuculline (GABA(A) receptor antagonist). The EPSPs evoked by ventral stimulation were persistently increased after tetanic stimulation (5 Hz, 300 pulses/train, 2 trains, train interval 10 min) in 6 of 12 tested IMM neurons. The amplitude of EPSPs was potentiated to more than 120% of control level (when analyzed at 45 min of enhancement, P<0.05, n=5), which lasted at least 30 min and then could be referred to as LTP. Moreover, area under curve, duration and max rise slope of EPSPs were also enhanced (P<0.05), while no significant changes were observed in the electrophysiological parameters of IMM neurons following induction of LTP (P>0.05). These results suggest that the intracellular recording techniques in the chick brain slices can be used to perform multi-parameter analysis of synaptic responses and their LTP.