Effects of caffeine injection in paradoxical sleep window on memory in rat

زمینه و هدف: برخی محققین عقیده دارند که پس از یادگیری برخی اعمال، میزان خواب REM در دوره هایی خاص افزایش می‌یابد و در طی برخی از این دوره‌ها پردازش و تثبیت حافظه صورت می‌گیرد. این دوره‌های خاص به عنوان پنجره‌های خواب متناقض مطرح گردیده‌اند. این پژوهش با هدف بررسی نقش آگونیست ها و آنتاگونیست‌های آدنوزینی و استیل کولینی در پنجره‌های خواب متناقض و تاثیر آن ها بر حافظه انجام شد. روش‌ بررسی: در این مطالعه تجربی موش‌های صحرایی نر تحت آموزش فعال دو طرفه یک جلسه 100 تریالی قرار گرفتند. آن دسته از حیواناتی که به مرز70 یادگیری رسیدند به 6 گروه دارویی و 2 گروه دارو-محرومیت تقسیم شدند. در بخش دارویی به ترتیب به هر یک از گروه ها سالین، کافئین ( mg/kg25)، آدنوزین ( mg/kg7)، آدنوزین ( mg/kg50)، فیزوستیگمین (mg/kg1/0) و اسکوپولامین ( mg/kg5) به صورت درون صفاقی تزریق گردید. در بخش دارو- محرومیت حیوانات گروه اول در دوره 4-1 ساعت پس از یادگیری از خواب REM محروم شدند و به حیوانات گروه دوم علاوه بر محرومیت، کافئین ( mg/kg25) تزریق گردید. میزان حافظه در تمام گروه ها یک هفته بعد مورد آزمایش قرار گرفت. یافته‌ها: تزریق کافئین باعث تقویت حافظه گردید (05/0

Borna disease virus (BDV) infection in psychiatric patients and healthy controls in Iran

Background Borna disease virus (BDV) is an evolutionary old RNA virus, which infects brain and blood cells of humans, their primate ancestors, and other mammals. Human infection has been correlated to mood disorders and schizophrenia, but the impact of BDV on mental-health still remains controversial due to poor methodological and cross-national comparability. Method This first report from the Middle East aimed to determine BDV infection prevalence in Iranian acute psychiatric disorder patients and healthy controls through circulating immune complexes (CIC), antibodies (Ab) and antigen (pAg) in blood plasma using a standardized triple enzyme immune assay (EIA). Samples of 314 subjects (114 psychiatric cases, 69 blood donors, and 131 healthy controls) were assayed and data analyzed quantitatively and qualitatively. Results CICs revealed a BDV prevalence of one third (29.5%) in healthy Iranian controls (27.5% controls; 33.3% blood donors). In psychiatric patients CIC prevalence was higher than in controls (40.4%) and significantly correlating with bipolar patients exhibiting overt clinical symptoms (p = 0.005, OR = 1.65). CIC values were significantly elevated in bipolar (p = 0.001) and major depressive disorder (p = 0.029) patients as compared to controls, and in females compared to males (p = 0.031). Conclusion This study supports a similarly high prevalence of subclinical human BDV infections in Iran as reported for central Europe, and provides again an indication for the correlation of BDV infection and mood disorders. Further studies should address the morbidity risk for healthy carriers and those with elevated CIC levels, along with gender disparities

Ventral tegmental area inactivation suppresses the expression of CA1 long term potentiation in anesthetized rat.

The hippocampus receives dopaminergic projections from the ventral tegmental area (VTA). Modulatory effect of dopamine on hippocampal long term potentiation (LTP) has been studied before, but there are conflicting results and some limitations in previous reports. Most of these studies show a significant effect of dopamine on the late phase of LTP in CA1 area of the hippocampus, while few reports show an effect on the early phase. Moreover, they generally manipulated dopamine receptors in the hippocampus and there are few studies investigating influence of the VTA neural activity on hippocampal LTP in the intact brain. Besides, VTA neurons contain other neurotransmitters such as glutamate and GABA that may modify the net effect of dopamine. In this study we examined the effect of VTA reversible inactivation on the induction and maintenance of early LTP in the CA1 area of anesthetized rats, and also on different phases of learning of a passive avoidance (PA) task. We found that inactivation of the VTA by lidocaine had no effect on CA1 LTP induction and paired-pulse facilitation, but its inactivation immediately after tetanic stimulation transiently suppressed the expression of LTP. Blockade of the VTA 20 min after tetanic stimulation had no effect on the magnitude of LTP. Moreover, VTA inactivation immediately after training impaired memory in the passive avoidance task, while its blockade before or 20 min after training produced no memory deficit. It can be concluded that VTA activity has no effect on CA1 LTP induction and acquisition of PA task, but involves in the expression of LTP and PA memory consolidation

Effect of interaction between acute administration of morphine and cannabinoid compounds on spontaneous excitatory and inhibitory postsynaptic currents of magnocellular neurons of supraoptic nucleus

Objective(s): Opioids and cannabinoids are two important compounds that have been shown to influence the activity of magnocellular neurons (MCNs) of supraoptic nucleus (SON). The interaction between opioidergic and cannabinoidergic systems in various structures of the brain and spinal cord is now well established, but not in the MCNs of SON. Materials and methods: In this study, whole cell patch clamp recording of neurons in rat brain slice was used to investigate the effect of acute morphine and cannabinoid administration on spontaneous inhibitory and excitatory spostsynaptic currents (sIPSCs and sEPSCs) in MCNs. Results: Bath application of morphine produced an increase in sEPSCs frequency and a decrease in sIPSCs frequency. In contrast, bath application of URB597 (fatty acid amide hydrolase (FAAH) inhibitor) produced a decrease in sEPSCs frequency but an increase in sIPSCs frequency. WIN55212-2 (cannabinoid receptor agonist) decreased both sIPSCs and sEPSCs frequencies of MCNs. Co-application of morphine and URB597 attenuated the effect of morphine on MCNs. Conclusion: Taken together, these data indicated that at the cellular level, pharmacological augmentation of endocannabinoids could attenuate morphine effects on MCNs

The effect of intra-VTA injection of saline or lidocaine immediately after tetanic stimulation on the expression of Schaffer-CA1 LTP.

<p>A) In both groups LTP was induced, but in the lidocaine group the magnitude of LTP was significantly lower than the control during the first 20 minutes (<i>p</i> = 0.029 for the time point of 1 min, and for the time points of 5, 10, 15 and 20 min <i>p</i> = 0.042, <i>p</i> = 0.012, <i>p</i> = 0.010, and <i>p</i> = 0.031, respectively). The data are shown as mean ± SEM. Inset: Exemplar original analog traces showing the magnitude of LTP in the saline (S) and lidocaine (L) groups for the first 20 min after HFS. The vertical scale bar corresponds to 1 mV and the horizontal to 5 ms. B) When fEPSPs were averaged in 10 min periods after the injection, difference between saline and lidocaine groups remained significant for 30 min (for 1–10 min <i>p</i> = 0.025, for 10–20 min <i>p</i> = 0.014, and for 20–30 min <i>p</i> = 0.034). Bar charts represent means ± SEM of fEPSPs.</p

Baseline synaptic response in Schaffer–CA1 pathway is not affected by lidocaine injection into the VTA.

<p>No significant differences observed between lidocaine versus saline groups during 2 h of recording. The data are shown as mean ± SEM. Inset: Original analog traces showing evoked responses in the CA1 stratum radiatum after saline (S) and lidocaine (L) injection. The vertical scale bar corresponds to 1 mV and the horizontal to 5 ms.</p

The effect of pre-training inactivation of the VTA on acquisition of PA task.

<p>A) Both saline and lidocaine groups required the same number of trials to attain criterion performance (2.33±0.42 for saline, 2.16±0.16 for lidocaine; Mann-Whitney <i>U</i>-test: <i>p</i> = 0.92), indicating that pre-training blockade of the VTA did not impair acquisition of the PA task. B) Measurement of memory 24 h after training showed STL and TDC were not statistically different between the two groups indicating pre-training inactivation of the VTA had no effect on the retention of PA, although there was a trend for lower STL and higher TDC in the lidocaine group.</p

Paired-pulse facilitation of fEPSPs recorded in the CA1 stratum radiatum after stimulation of Schaffer collaterals.

<p>PPF index is defined as slopes of fEPSP2/fEPSP1. No significant differences in PPF index were observed before and after saline or lidocaine injection and between the two experimental groups at different inter-pulse intervals. Inset: Original analog traces showing paired-pulse responses in the CA1 stratum radiatum at inter-pulse intervals of 20, 50, and 100 ms. The vertical scale bar corresponds to 1 mV and the horizontal to 10 ms.</p