Molecular and Cellular Mechanisms Underlying Spatial Learning

Understanding the molecular and cellular mechanisms underlying learning and memory is one of the most exciting topics in the field of Neuroscience. Learning is thought to occur through activity-dependent synaptic modification in the neuronal network. The hippocampus, is an excellent structure to study synaptic plasticity and learning, because of its anatomy and network. Most of the studies in this thesis were performed on the hippocampus to unravel the molecular and cellular mechanisms underlying spatial learning. Molecular and cellular studies of mechanisms underlying mammalian learning and memory have focused almost exclusively on postsynaptic function. However, in chapter 2 we reveal a presynaptic mechanism that modulates learning and synaptic plasticity in mice. Using transgenic mice expressing a constitutively active form of H-ras (H- rasG12V), we studied the H-Ras/ERK/Syn I pathway and showed that in these mice ERK-dependent phosphorylation of synansin I is increased and causes several presynaptic changes. Calcium-calmodulin dependent protein kinase II (CaMKII) is a protein kinase, which detects Ca2+ signals and can phosphorylate many target proteins as well as itself. This auto-phosphorylation is critical for its role in LTP and learning. However, in chapter 3 we show that although CaMKII is required for normal presynaptic function, its ability to phospho

Thinning cycles as the key factor to improve stand productivity in alder plantations

Considering the high demand for wood and other forest ecosystem services, planning and managing forest plantations to mitigate and answer these increasing issues is necessary. Thinning is one of the most common managing practices for manipulating the growth of planted trees. However, studies about the impact of the thinning-cycle on stand and soil properties are rare for Alnus subcordata C.A.Mey. in Hyrcanian Forests. The aim of this study was to investigate the effect of thinning-cycles on stand and soil properties in the Alnus subcordata plantation in the Hyrcanian Forests, Northern Iran. Three neighboring alder plantations were selected with different thinning treatment cycles: the one-time thinning-cycle (T1, thinned in 2007), three-time thinning-cycle (T3, thinned in 2005, 2010, and 2015), and no thinning as the control (C). In each plantation, 15 plots (20×20 m) were systematic-randomly established (75×50 m grid). In each plot, the characteristics of trees (diameter at breast height (DBH) and total height) and total percentage of vegetation cover were recorded. Soil physiochemical properties were studied by taking samples (0-10 cm) from each plot. The highest value of DBH, total height, tree volume, and basal area and the lowest amount of the total height to DBH ratio were observed in T3. The highest levels of vegetation diversity, evenness, and richness indices were obtained in T3. Soil moisture was significantly higher in the control. The soil pH, electrical conductivity, nitrogen, and potassium were significantly higher in T3. According to the principal component analysis, there was no difference between T1 and control. For this reason, T3 was a more beneficial treatment. Our findings suggested that in alder plantations, the reduction of above and belowground competition via the three-time thinning-cycle, in addition to the financial benefits, not only improves the quality and quantity of the remaining trees but also has a significant potential to improve soil productivity

Ruta graveolens and rutin, as its major compound: investigating their effect on spatial memory and passive avoidance memory in rats

Context: There are numerous pharmacological activities for Ruta graveolens and its bioactive constituent, rutin, on learning and memory. Objective: This study aimed to examine the effect of R. graveolens and rutin on memory in rats. Materials and methods: In this study animals were treated with the hydroalcholic extract of R. graveolens and rutin by IP injection for 10 days. Behavioural and biochemical tests as well as HPLC analysis and antioxidant activity of extract have been evaluated. Results: R. graveolens extract and rutin significantly increased learning and improved spatial memory, as well as secondary latency; moreover, there were significant increases in the serum and brain antioxidant capacity as well as the level of TBARS in serum and brain tissues. Results also showed that R. graveolens has significant DPPH radical scavenging effect (IC50: 159.17 +/- 1.56 mu g/mL). The HPLC analysis of extract showed that caffeic acid (19.92 +/- 0.01), rutin (40.15 +/- 0.01), and apigenin (0.84 +/- 0.01) mg/g of dry extract are the main components of the extract. Discussion and conclusion: Regarding the effects of R. graveolens extract and rutin on animal brain cells, memory function, and learning, additional studies, including clinical trials, might be beneficial in producing natural supplementary drugs from this herb

Prevalence and risk factors of urethral, penile, and scrotal cancers in Iranian men during 2004-2015: A national cancer registry-based study

Introduction: Urethral, penile, and scrotal cancers are rare and represent less than 1% of all malignancies. However, they are associated with a high mortality rate and have a significant effect on patients’ quality of life. Penile and urethral cancers comprise 0.6% of all urological cancers. Because of ethnic, geographical, and cultural diversity, risk factors and cancer patterns vary in different communities. We aimed to provide valid information on the prevalence, incidence, and epidemiology of urethral, penile, and scrotal cancers using the National Registry on Cancer of Iran. Methods: This retrospective study of 465 patients included all known cases of urethral, penile, and scrotal cancers from the Department of National Registry on Cancer at the Ministry of Health and Medical Education in Iran during 2004-2015. This study examined the demographic characteristics of patients and discussed the risk factors and possible causes of the above-mentioned cancers. Results: The mean ±SD age at the time of registration was 58.49±20.82 years. The highest and lowest proportions of cases belonged to Tehran/Alborz (14.2%) and Mazandaran (0.65%) provinces, Iran, respectively. Regarding the distribution of records according to a year of registration, these cancers were more prevalent in 2014, and less prevalent in 2004. Conclusion: Urethral, penile, and scrotal cancers were more common in Tehran and Alborz. There was a strong possibility that the prevalence of these cancers is linked to the industrial nature of Tehran and Alborz and the prevalence of human papillomavirus

Effect of Rheum Ribes Hydro-Alcoholic Extract on Memory Impairments in Rat Model of Alzheimer's Disease.

Some animal models have been used to study Alzheimer's disease (AD). AD is an irreversible progressive neurodegenerative disease and the most common cause of dementia. Animal studies have shown that there is a relation between decrease in cholinergic functions in the nucleus basalis of Meynert (NBM) and loss of learning capability and memory. The aim of this study was to investigate the effect of Rheum ribes extract (RR) on memory deficit in one of the rat models of AD. Plant (1500gr) was collected from Saman (kahkesh) region of Chaharmahal Va Bakhtiari province in Iran. RR hydro-alcoholic extracts were prepared using maceration method. Rat model of Alzheimer was induced by Nucleus Basalis of Meynert lesions (NBML). Animals (n = 32) received extracts for 20 days and then passive avoidance and Morris water maze tasks were performed for memory evaluation. FRAP and HPLC methods were used for measurement of the antioxidant and Malondialdehyde (MDA) levels in blood. In water maze experiment, probe trial results showed that NBML group spent significantly less time in target quadrant, in which the platform was located on the preceding day. In addition, the time spent in target quadrant was significantly increased in NBML + RR groups (250 and 500 mg/kg) compared to the NBML group. In passive avoidance task, mean initial latency time and step-though latency were significantly decreased in NBML group. RR extracts significantly prolonged step-through latency in NBML + RR groups. Results of this study suggest that Rheum ribes extracts can improve memory deficits induced by bilateral NBM lesions in rats

The effect of hydro-alcoholic extract of dried Ficus carica on spatial learning and memory in mice

زمینه و هدف: انجیر (Ficus carica) دارای اثرات گوناگون درمانی است. در مطالعات قبلی مشخص شده است که این میوه ملین بوده و در درمان بیماری های متعددی از جمله بواسیر، نقرس و صرع نافع می باشد. به علت وجود مقادیر زیاد فسفر در انجیر، به نظر می رسد که این میوه در پرورش هوش و حافظه موثر باشد. لذا این مطالعه به منظور بررسی اثرات احتمالی عصاره هیدروالکلی انجیر بر یادگیـــری و حافظه فضایی در موش های سوری انجام شد. روش بررسی: در این مطالعه تجربی- آزمایشگاهی، 32 سر موش سوری به صورت تصادفی به چهار گروه تقسیم شدند. گروه های کنترل، نرمال سالین و سه گروه آزمایشگاهی دیگر به ترتیب دوزهای 100، 200 و 400 میلی گرم در کیلوگرم عصاره هیدروالکلی انجیر را بصورت داخل صفاقی (ip) دریافت کردند. عصاره از طریق خیساندن پودر انجیر خشک شده در الکل 80 تهیه شد. تزریق سالین یا عصاره برای مدت هفت روز (یک بار در هر روز) انجام می شد و بلافاصله پس از آن، دوره یادگیری با استفاده از ماز آبی موریس شروع می شد که 5 روز طول می کشید. در صورت ایجاد یادگیری، آزمایش پروب (Probe trial) برای تست حافظه فضایی کوتاه مدت و بلند مدت در روزهای بعدی انجام می شد. در پایان داده ها با استفاده از آزمون ANOVA و آزمون های تعقیبی (LSD) Fisher least significantو توکی مورد تجزیه و تحلیل آماری قرار گرفت. یافته ها: آزمایشات نشان داد که عصاره انجیر تاثیر معنی داری در روند یادگیری فضایی در مدل ماز آبی موریس ندارد. ارزیابی حافظه کوتاه مدت در روزهای 6 و 8 تفاوت معنی داری بین گروه های دریافت کننده سالین و عصاره انجیر نشان نداد، ولی در روز 10 کاهش معنی داری در حافظه کوتاه مدت در گروه های دریافت کننده عصاره انجیر در مقایسه با گروه سالین مشاهده شد (05/0

The effect of hydro-alcoholic extract of Melissa officinalis on learning and spatial memory in Balb/c mice

زمینه و هدف: بادرنجبویه، (Melissa officinalis)، دارای اثرات گوناگون درمانی از جمله اثرات تسکینی، آنتی اکسیدانی و ضد اسپاسم بوده و به صورت یک داروی آرام بخش و کمک دهنده ی خواب استفاده می شود. در این مطالعــه اثر تزریق داخل صفاقی عصاره هیدروالکلی بادرنجبویه بر یادگیری و حافظه در موش های سوری به روش ماز آبی موریس بررسی شد. روش بررسی: در این مطالعه تجربی تعداد 32 سر موش سوری نژاد Balb/c در چهار گروه تصادفی قرار گرفتند. به گروه کنترل، سرم فیزیولوژی و به سه گروه آزمایشی دیگر دوزهای 25، 50 و 100 میلی گرم به ازای هر کیلوگرم وزن بدن عصاره هیدروالکلی بادرنجبویه برای مدت هفت روز تزریق شد. با استفاده از روش ماز آبی موریس، میزان یادگیری حیوانات به مدت 5 روز متوالی ارزیابی شد. پس از تکمیل دوره یادگیری، در روزهای 5، 7 و 9 آزمایش پروب (Probe trial) برای ارزیابی حافظه کوتاه مدت و بلند مدت انجام شد. داده ها با استفاده از آزمون های آماری آنالیز واریانس یکطرفه و توکی تجزیه و تحلیل شد. یافته ها: میزان یادگیری در حیوانات دریافت کننده عصاره بادرنجبویه تفاوت معنی داری با گروه دریافت کننده سالین نداشت. نتایج اولین آزمایش پروب تاثیر مثبت دوز کم عصاره بادرنجبویه (دوز 25 میلی گرم در کیلوگرم) بر حافظه کوتاه مدت را نشان داد (05/0

Allium hirtifolium Boiss: Radical scavenging property and the lowering effects on blood fibrinogen and factor VII

Enhancement of blood fibrinogen or factor VII increases cardiovascular diseases. Allium hirtifolium Boiss (Mosir) has been shown to have cardioprotective effect. This study, therefore, aimed to evaluate the effects of Allium hirtifolium Boiss on factor VII and fibrinogen blood levels. Its radical scavenging property was also measured. Twenty four NewZealand male rabbits were randomly designated into 3 groups of 8 and were fed for 60 days with normal diet, hypercholestrol (1%) diet or hypercholestrol (1%) diet+Mosir. At the beginning and 60 days after the start of the study, the blood fibrinogen and factor 7 were measured and compared in different groups. The Mosir radical scavenging property was measured using the beta-carotene linoleate method. The blood fibrinogen and factor 7 were higher in hypercholesterolemic group (26.7 +/- 329.22 and 17.1 +/- 277.7mg/dl) compared to normal diet group (13.7 +/- 287.25 and 18.2 +/- 230.0 mg/dl, respectively) (P<0.05), at the end of the experiment. The amount of blood fibrinogen and factor 7 were decreased in hypercholesterol+Mosir group (23.9 +/- 180.00 and 53.3 +/- 237.0 mg/dl) compared to hypercholesterol diet group (P<0.05). radical scavenging activity of Mosir extract was 52.1 +/- 3.3%. Mosir may have beneficial effect on heart by decreasing blood fibrinogen and factor 7 as cardiovascular risk factors. These effects of Mosir should be considered carefully in patients with hemostatic disorders. Asgari. S, Rafieian-kopaei. M, Pourgheysari. B, Ansari-Samani. R, Deris F, Shahinfard. N, Hojjati. MR and Salimi. M. Allium hirtifolium Boiss: Radical scavenging property and the lowering effects on blood fibrinogen and factor VII. Life Sci J 2012;9(3):1793-1798] (ISSN:1097-8135). http://www.lifesciencesite.com. 25

Kinase activity is not required for αCaMKII-dependent presynaptic plasticity at CA3-CA1 synapses

Using targeted mouse mutants and pharmacologic inhibition of αCaMKII, we demonstrate that the αCaMKII protein, but not its activation, autophosphorylation or its ability to phosphorylate synapsin I, is required for normal short-term presynaptic plasticity. Furthermore, αCaMKII regulates the number of docked vesicles independent of its ability to be activated. These results indicate that αCaMKII has a nonenzymatic role in short-term presynaptic plasticity at hippocampal CA3-CA1 synapses. © 2007 Nature Publishing Group