Correlation between cognitive development and levels of dopamine and 3,4-dihydroxyphenylacetic acid in the hippocampus in 80-day-old neonatal rats born of fear-impaired pregnant rats / 中国比较医学杂志

Objective To investigate the correlation between cognitive development and levels of dopamine(DA) and 3,4-dihydroxyphenylacetic acid(DOPAC)in the hippocampus of 80-day-old neonatal rats born of fear-impaired pregnant rats. Methods The pregnant rat model of fear-impaired kidney was established by watching other rats shocked with electricity. The cognitive development of the neonatal rats was assessed by Morris water maze test at 80 days after birth. The brain microdialysis samples of the right hippocampus were collected using a stereotaxic instrument, and the levels of DA and DOPAC were determined by HPLC-ECD. Results Compared with the control group, the mean escape latency of the 80-day-old neonatal rats in the model group was increased. Their swimming speed was slower. The 20% time spent in the peripheral zone became longer, and the frequency of platform crossing was decreased, showing significant differences(P< 0.05). The levels of DA and DOPAC in the extracellular fluid of the hippocampus of the 80-day-old neonatal rats in the model group were decreased at each time points of perfusion, showing a significant difference(P <0.05). The level of DA, a kind of monoamine neurotransmitter in the hippocampus, was positively correlated with the mean escape latency,the frequency of passing the platform of the 80-day-old rats,while was negatively correlated with the 20% time spent in the peripheral zone, with a significant correlation(P < 0.05). In addition, there was a positive correlation between the DOPAC level and the mean escape latency, the frequency of passing the platform(P< 0.05). Conclusions Fear-impaired pregnant rats can affect the spatial learning and memory ability of their 80-day-old neonatal rats,with reduction in the levels of DA and DOPAC in the hippocampus, which is closely correlated with the cognitive development of the neonatal rats.

Effect of meloxicam on CUMS-induced depressive-like behavior in rats and its preliminary mechanism / 中国药理学通报

Aim To explore the effect of meloxicam on the CUMS-induced depressive-like behaviors in rats and its preliminary mechanism. Methods The rats were exposed to CUMS procedure for 6 weeks to estab-lish the model of depression. Meloxicam(1,3 mg· kg-1 ) and sertraline(5 mg·kg-1 ) were administered to rats from 22d of the stress procedure(once a day,for 21 days,p. o. ) . Depressive-like behaviors were evalu-ated by the open-field test and force swimming test. The levels of PGE2 and TNF-αin cortex were measured by ELISA. Moreover, the concentrations of NE, DA, DOPAC and 5-HIAA were also measured by HPLC, and the protein expression of 5-HT1 AR in cortex was analyzed by the immunohistochemistry. Results Com-pared with the rats of normal control group,the vertical and horizontal movement scores of rats in the open-field test were decreased and the immobility time in the forced swimming test was increased in model group. The levels of PGE2 and TNF-α were both increased signifi-cantly,whereas the concentrations of NE, DA, DOPAC and 5-HIAA were decreased and the expression of 5-HT1AR was reduced in cortex. Compared with the rats of model group, meloxicam significantly improved the depressive behaviors of rats in experimental groups and reversed the content of PGE2 ,TNF-α,NE,DA,DOPAC and 5-HIAA, as well as the expression of 5-HT1AR. Conclusion Meloxicam has a significant protective effect on CUMS-induced depressive-like behaviors, and the protective mechanism might be related to atten-uating inflammation response and reconstructing the balance of the monoamine neurotransmitter system in rat cortex.

Modulation of post-coital dopaminergic tone by prior parity

The aim of this study was to investigate the possible effects of reproductive experience on dopaminergic profile in three different brain tissues, hypothalamus, striatum and cortex in rats on 7th-8th day of pregnancy during the light-dark shift (between 1700-1900h). Results showed that in hypothalamus, dopamine levels increased and DOPAC/DA decreased as a function of parity. In cortex, no differences were observed. In striata, the haloperidol-induced HVA and HVA/DA increases were less intense in experienced animals. These findings suggested that reproductive experience produced functional central changes during pregnancy, with different neurochemical responses depending on the brain region.

A dopamina age nos níveis endócrino, neuroquímico e comportamental. A experiência reprodutiva modula alguns destes aspectos: a dopamina está aumentada no estriato e no hipotálamo de ratas muiltigrávidas entre 12:00-14:00 horas. A sensibilidade dos terminais dopaminérgicos também parece ser modulada por uma experiência reprodutiva prévia. Nosso objetivo foi o de investigar os possíveis efeitos da experiência reprodutiva no perfil dopaminérgico de três diferentes tecidos cerebrais, hipotálamo, estriato e córtex em ratas no 7º-8º dia de gestação durante a fase de virada do ciclo claro-escuro (entre 17:00-19:00h). Nossos resultados mostraram que os níveis dopaminérgicos no hipotálamo aumentaram e o índice DOPAC/DA diminuiu em multigrávidas quando comparadas às primigrávidas. No córtex, nenhuma diferença foi encontrada. No estriato, o aumento de HVA e HVA/DA induzidos pelo haloperidol foi menos intenso nos animais experientes. Nossos resultados sugerem que a experiência reprodutiva produz alterações funcionais centrais durante a gestação, com diferentes respostas neuroquímicas de acordo com a região cerebral.

Study of dopamine transporter in the rat 6-hydroxydopamine Parkinson's disease model

BACKGROUND: Neuroprotective therapy is essential in the management of Parkinson's disease(PD). As symptomatic benefit of a treatment may clinically mask the disease progression, an evaluation of the effect of a neuroprotective therapy should be based on objective measurement of in vivo dopaminergic integrity: Nuclear imaging techniques such as SPECT or PET can visualize dopaminergic system using dopamine transporter ligands and show the promise for this purpose. The objective of this study is to examine the changes of dopamine transporter in the animal model of PD and those correlations with behavioral and biochemical changes. METHODS: We injected 6-hydroxydopamine into the substantia nigra in Sprague-Dawley rats to establish the unilateral PD model, and examined the rotation response after apomorphine injection as a behavioral aspect of the animal model. And we also measured the dopamine and DOPAC level in the striata and the dopamine transporter by [3H]-mazindol autoradiography. RESULTS: We observed that the rats showed turning behavior only after severe reduction of dopamine and DOPAC. There was a strong inverse correlation between rotation behavior and striatal dopamine, DOPAC and dopamine transporter density. There was a positive and strong linear-correlation between dopamine transporter density and dopamine or DOPAC levels. CONCLUSION: Measurement of dopamine transporter gives a good estimate of striatal dopamine level in an animal model of PD. In vivo measurement of dopamine transporter will give an objective information on the integrity of presynaptic nigrostriatal dopaminergic system.