Retracted: Allopregnanolone restores the tyrosine hydroxylase-positive neurons and motor performance in a 6-OHDA-injected mouse model.

AIMS: It has been reported that allopregnanolone (APα) promotes the neurogenesis of the neural progenitor cells (NPCs) in the subventricular zone (SVZ) and prevents the decrease of dopaminergic neurons in 6-hydroxydopamine (6-OHDA)-treated mice by binding to γ-aminobutyric acid A receptor (GABAAR) and then opening voltage-gated L-type Ca2+ channel, but the underlying mechanisms remain elusive. The aim of this study was to explore the possible involvement of GABAAR and calcium/calmodulin-dependent protein kinase II delta 3 (CaMKIIδ3) in this process. METHODS: 6-OHDA-treated mice and primary cultured midbrain cells were administrated with APα and GABAAR antagonist bicuculline (Bic), and the proliferation and differentiation of NPCs, the tyrosine hydroxylase (TH)-positive neurons and their fibers, the expression levels of CaMKIIδ3 and brain-derived neurotrophic factor (BDNF), and motor functions were measured using ELISA, immunohistochemical staining, real-time RT-PCR, Western blot, and behavioral test. RESULTS: Allopregnanolone significantly promoted the phosphorylation of cytoplasmic CaMKIIδ3 and its nuclear translocation by binding to GABAAR, which, in turn, increased the expression levels of BDNF. This may account for the findings that the exogenous APα enhanced the proliferation and differentiation of NPCs, and ameliorated the nigrostriatal system and behavioral performance in 6-OHDA-treated mice. CONCLUSIONS: Allopregnanolone may directly activate GABAAR, which, in turn, enhance the proliferation and differentiation of NPCs via upregulating the expression levels of CaMKIIδ3, and finally contribute to the restoration of dopaminergic neurons in 6-OHDA-treated mice.

Deletion of autophagy-related gene 7 in dopaminergic neurons prevents their loss induced by MPTP.

Parkinson's disease (PD) is a neurodegenerative disease caused by a gradual loss of midbrain dopaminergic (mDA) neurons in the substantia nigra pars compacta (SNpc) during aging. 1-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) is one of the neurotoxins used widely to induce PD-like symptoms in PD animal models, including rodents and non-human primates. It has been reported that deletion of autophagy-related gene 7 (Atg7) in the brain results in a reduction of mDA neurons in adulthood. In this study, we used tyrosine hydroxylase (TH)-Cre mice to generate conditional knockout (CKO) mice with the specific deletion of Atg7 in mDA neurons. Consistent with previous reports, adult Atg7 CKO mice contained fewer TH-positive mDA neurons compared with wild-type (WT) controls. TH-expressing neurons containing puncta-like structures with p62 and ubiquitin immunoreactivity were observed in the midbrain of Atg7 CKO mice but were not detected in control mice. However, MPTP-induced loss of mDA neurons was not observed in Atg7 CKO mice. Our results indicate that Atg7-involved autophagy is required not only for the survival of mDA neurons in the mouse brain, but also for MPTP-induced mDA neuron degeneration.

[Effect of curcumin on the learning, memory and hippocampal Ca+/CaMK II level in senescence-accelerated mice].

OBJECTIVE: To explore effect of curcumin in different concentrations on learning and memory of senescence-accelerated mice (SAM) and their possible mechanisms. METHODS: Mice were randomly divided into six groups: the SAMR1 normal control group, the SAMP8 model control group, the SAMP8 + solvent (the peanut oil) control group, SAMP8 + low, middle and high dose curcumin groups. Mice were gastrogavage for 25 successive days. On the next day of ending the experiment, changes of learning and memory in mice of each group were observed by Morris water maze. The hippocampal [Ca2+] was determined. Expressions of hippocampal calmodulin-dependent protein kinase II (CaMK II) and Calmodulin (CaM) mRNA were detected using Western blot and reverse transcription polymerase chain reaction (RT-PCR) respectively. RESULTS: The latency to find the hidden platform was remarkably prolonged, the hippocampal [Ca2+]i was markedly increased, the expression of CaMK II in the hippocampal membrane and the level of hippocampal CaM mRNA were significantly reduced in the SAMP8-model control group (P < 0.05, P < 0.01). The latency to find the hidden platform was remarkably shortened in the SAMP8 + middle dose curcumin and the SAMP8 + high dose curcumin groups (P < 0.01). The hippocampal [Ca2+]i was markedly lowered, the expression of CaMK II in the hippocampal membrane and the level of hippocampal CaM mRNA obviously increased in the SAMP8 + low, middle and high dose curcumin groups (P < 0.05, P < 0.01). CONCLUSION: Curcumin could improve learning and memory Ca2+/capacities of SAM by lowering hippocampal [Ca2+] overload, increase the hippocampal CaM mRNA level and CaMK II expression in the hippocampal dose-dependently.

[Effect of Rhizoma curcumae oil on the learning and memory in rats exposed to chronic hypoxia and the possible mechanisms.].

The effect of Rhizoma curcumae oil on the learning and memory in rats exposed to chronic hypoxia and the possible mechanisms were investigated. The rats were divided randomly into 5 groups (14 animals in each group): control, chronic hypoxia, chronic hypoxia with low (5 mg/kg body weight), middle (10 mg/kg body weight) and high (20 mg/kg body weight) concentrations of Rhizoma curcumae oil injection. The animals undergoing chronic hypoxia were exposed to hypoxia in a hypoxic chamber containing 10% O(2) and 5% CO(2) for 10 h/d, lasting 28 d. Morris water maze (MWM) test was used to obtain the scores of leaning and memory. The superoxide dismutase (SOD) activity and malonaldehyde (MDA) content were determined in the serum and hippocampus as well as [Ca(2+)](i) in the hippocampus. The expression of phosphorylated Ca(2+)/calmodulin-dependent protein kinase II (p-CaMKII) in the hippocampus was evaluated by using immunohistochemistry and Western blot. Compared with the control group, the chronic hypoxia group showed the following changes: (1) The escape latency to the hidden platform was remarkably prolonged (P<0.05); (2) The content of MDA and [Ca(2+)](i) were obviously higher, but the activity of SOD and the expression of p-CaMKII were significantly lower (P<0.05, P<0.01). Compared with the chronic hypoxia group, groups with Rhizoma curcumae oil injection had the following changes: (1) The escape latency to the hidden platform was remarkably shorter in 10, 20 mg/kg body weight groups (P<0.05); (2) The content of MDA and [Ca(2+)](i) were markedly decreased in 5, 10, 20 mg/kg body weight groups (P<0.05, P<0.01), but the activity of SOD in the serum and the expression of p-CaMKII were significantly higher in 10, 20 mg/kg body weight groups (P<0.05, P<0.01). The results showed that the capacity of learning and memory was degraded following chronic hypoxia. The decrease in MDA content and [Ca(2+)](i) and (or) the increase in SOD activity and p-CaMKII expression might participate in the enhancing effect on learning and memory induced by Rhizoma curcumae oil.

[Study on angle and depth of needle insertion in acupuncture at Zusanli (ST 36)].

OBJECTIVE: To provide an appropriate angle and depth of needle insertion in acupuncture at Zusanli (ST 36) and avoid injuring the nerve and blood vessel and exert the most effect. METHODS: Eighty adult lower-limb samples were used to dissect and observe the relative layered structures and adjoining important nerves and blood vessels in needling Zusanli (ST 36) according to the national standard. RESULTS: The needling depth from the skin to the interosseous membrane and from the skin to posterior border of tibialis posterior is (2.22 +/- 0.31) cm and (4.42 +/- 0.53) cm, respectively. There are flabellate branches of anterior tibial arteries and deep peroneal nerves around the needle in the superficial layer of interosseous membrane. The vessel and nerve bundles containing tibial nerve and posterior tibial vessels can be touched when the needle body past through tibialis posterior. CONCLUSION: It is recommended that ideal average depth of acupuncture is 2.22 cm and the maximum depth is 4.42 cm for oblique needling Zusanli (ST 36). When it is injected, the needle should be perpendicularly inserted or deviated slightly to the direction of tibia and paralleled to medial surface of tibia. And the safe needling depth is generally less than 5 cm. The point of the body surface between tibialis anterior and extensor digitorum longus at 3 cun below Dubi (ST 35) is also an effectively stimulating point.

Changes of learning, memory and levels of CaMKII, CaM mRNA, CREB mRNA in the hippocampus of chronic multiple-stressed rats.

BACKGROUND: The effect of chronic stress on cognitive functions has been one of the hot topic in neuroscience. But there has been much controversy over its mechanism. Such single stressor applied in the past could not simulate complicated living circumstances that people confronted with. The aim of this study was to investigate the effects of chronic multiple-stress on learning and memory as well as on the levels of calcium/calmodulin-dependent protein kinase II (CaMKII), calmodulin (CaM) mRNA, and cAMP-response element binding protein (CREB) mRNA in the hippocampus of rats. METHODS: The rats were divided randomly into stressed and control groups. The stressed group was given chronic multiple-stress for 6 weeks to set up a chronic multiple-stressed model. The rats' performance of spatial learning and memory was tested using Morris Water Maze (MWM) and Y-maze. Meanwhile, the expressions of CaMKII, CaM mRNA and CREB mRNA of rats' hippocampus were detected by immunohistochemistry, Western blot and reverse transcription-polymerase chain reaction (RT-PCR), respectively. In addition, the width of synaptic cleft and the thickness of post-synaptic densities (PSD) were observed in the hippocampal CA3 region of rats by electron microscopy. RESULTS: After exposure to chronic multiple-stress for 6 weeks, the ability of learning and memory of the stressed group was higher than that of the control group (P < 0.05, P < 0.01). The width of synaptic cleft was smaller and the thickness of PSD was larger in the hippocampal CA3 region of the stressed group than in that of the control group (P < 0.01). The CaMK II immunostaining of the stressed group was stronger than that of the control group in the stratum radiatum and oriens of the hippocampal CA1 and CA3, especially in the stratum oriens. Quantitative analysis indicated that the expression of CaMK II, CaM mRNA, and CREB mRNA in the hippocampus of the stressed group was higher than that of the control group (P < 0.05, P < 0.01). CONCLUSIONS: The capacity of learning and memory can be enhanced after chronic multiple-stress. The increased levels of CaMK II, CaM mRNA, and CREB mRNA may contribute to the enhancing effect of chronic multiple-stress on learning and memory.

[Chronic multiple stress enhances learning and memory capability in rats].

The present study aimed at investigating the effects of chronic multiple stress on learning and memory functions of rats. Adult male Wistar rats were randomly divided into stressed and control groups. Rats in the stressed group were irregularly and alternately exposed to the situation of vertical revolution, sleep deprivation, noise stimulation, and night illumination 6 h per day for 6 weeks to prepare a chronic multiple stressed model. Learning and memory performance of rats was measured by using Morris water maze first and Y-maze afterwards. Neurons in the dentate gyrus(DG), CA3 and CA1 regions of the hippocampus were stained by using Cresyl violet method and counted. The results showed that: (1) After chronic multiple stress, compared with the control rats, the escape latency to the hidden platform in Morris water maze was significantly shortened in stressed rats. In stressed and control groups, the escape latency periods were (15.89+/-9.15) s and (27.30+/-12.51) s, respectively, indicating that spatial memory of the stressed rats was stronger than that of the control ones. In brightness-darkness discrimination learning in the Y- maze, the correct trials and correct percentage of entering safe arm was remarkably increased in the stressed rats, the correct rates of stressed and control groups were (79.01+/-1.23)% and (66.12+/-1.61)%, respectively, indicating that brightness-darkness discrimination learning ability of the stressed rats was better than that of the control ones. (2) After chronic multiple stress, nerve cell density in DG, CA1 and CA3 of the hippocampus in stressed rats was higher than that of the control group, the cell densities in DG, CA1 and CA3 of the stressed and the control group were (223.78+/-26.52), (112.07+/-14.23) and (105.55+/-18.12) as well as (199.13+/-15.36), (92.89+/-13.69), and (89.02+/-15.77) respectively. These results suggest that the chronic multiple stress may enhance the capability of spatial memory and brightness-darkness discrimination learning of rats. Possible reasons for the chronic multiple stress-induced learning and memory enhancement of rats were also discussed.