hypothetical animal model for psychosis based on the silencing of GABAergic system

Although many studies have highlighted the role of gamma-aminobutyric acid [GABA] in the pathophysiology of psychosis, there is no drug-induced animal model in which GABA is manipulated. In this article we propose a hypothetical animal model for psychosis based on the silencing GABAergic system. The presentation also suggest Pre-Pulse Inhibition test as a preferred approach towards proving this hypothesis

Protection of hippocampal CA1 neurons against ischemia/reper-fusion injury by exercise preconditioning via modulation of Bax/ Bcl-2 ratio and prevention of caspase-3 activation

Introduction: Ischemia leads to loss of neurons by apoptosis in specific brain regions, especially in the hippocampus. The purpose of this study was investigating the effects of exercise preconditioning on expression of Bax, Bcl-2, and caspase-3 proteins in hippocampal CA1 neurons after induction of cerebral ischemia

Methods: Male rats weighing 260-300 g were randomly allocated into three groups [sham, exercise, and ischemia]. The rats in exercise group were trained to run on a treadmill 5 days a week for 4 weeks. Ischemia was induced by the occlusion of both common carotid arteries [CCAs] for 20 min. Levels of expression of Bax, Bcl-2, and caspase-3 proteins in CA1 area of hippocampus were determined by immunohistochemical staining

Results: The number of active caspase-3-positive neurons in CA1 area were significantly increased in ischemia group, compared to sham-operated group [P<0.001], and exercise preconditioning significantly reduced the ischemia/reperfusion-induced caspase-3 activation, compared to the ischemia group [P<0.05]. Also, results indicated a significant increase in Bax/Bcl-2 ratio in ischemia group, compared to sham-operated group [P<0.001]

Discussion: This study indicated that exercise has a neuroprotective effects against cerebral ischemia when used as preconditioning stimuli

Chronic ritalin administration during adulthood increases serotonin pool in rat medial frontal cortex

Ritalin has high tendency to be abused. It has been the main indication to control attention deficit hyperactivity disorder. The college students may seek for it to improve their memory, decrease the need for sleep [especially during exams], which at least partially, can be related to serotonergic system. Therefore, it seems worthy to evaluate the effect of Ritalin intake on mature brain. There are many studies on Ritalin effect on developing brain, but only few studies on adults are available. This study was undertaken to find Ritalin effect on serotonin transporter [SERT] density in medial frontal cortex [MFC] of mature rat. Thirty male Wistar rats were used in the study. Rats were assigned into five groups [n = 6 per group]: one control, two Ritalin and two vehicle groups. Twelve rats received Ritalin [20 mg/kg/twice a day] orally for eleven continuous days. After one week of withdrawal and another two weeks of rest, in order to evaluate short-term effects of Ritalin, six rats were sacrificed. Another six rats were studied to detect the long-term effects of Ritalin; therefore, they were sacrificed 12 weeks after the previous group. The immunohistochemistry was performed to evaluate the results. Immunohistochemistry studies showed a higher density of SERT in both 2 and 12 weeks after withdrawal from Ritalin intake in MFC of rat and there was no significant difference between these two groups. Our findings demonstrated both short- and long-term effects of Ritalin on frontal serotonergic system after withdrawal period

Distribution of age and location of chordoma in 39 cases and review of treatment options

Skull base chordomas are rare neoplasms arising from the notochord. Although histologically benign, these tumors are locally aggressive and present significant management challenges. There are some studies on chordoma cases but there was no study about Iranian cases. In this study we evaluated the location, age and gender of the patients with Chordoma in two referral centers in Tehran. A database of patients with chordoma tumors referred to two centers [Shariati and Imam Hospitals, Tehran] from 2001 to 2011 was retrospectively reviewed. In our subjects tumors affect men nearly twice as frequently as women, and they are most commonly diagnosed in middle-aged [mean age was 50.6]. Tumors typically occur in the axial skeleton and have a tendency for the spheno-occipital region of the skull base and sacral region. In adults 33.3% of chordomas involve the sacrococcygeal region, 53% occured at the base of the skull near the spheno-occipital area, and near 14% were found in the vertebral column. The cranial nerves mostly affected were abducens, oculomotor and trochlear, with some overlaps. All patients were treated with surgery and some cases referred for gamma-knife radiosurgery [GKS]. Findings of this study showed more involvement of males compare to females; that is different from other studies, however, few studies reported more male to female ratio. Despite the progress in current surgical techniques and some encouraging results with the use of targeted therapy, disease control and long-term prognosis of patients are still poor

Prenatal mercuric chloride exposure causes developmental deficits in rat cortex

Introduction: Environmental pollution with heavy metals such as mercury is a major health problem. Growing studies on the field have shown the deleterious effects of mercury on human and nonhuman nervous system, especially in infants, however the effects of prenatal exposure to mercuricchloride on cortical development are not yet well understood. The aim of this study was to investigate the effect of prenatal exposure to mercuric chloride on morphological characteristics of brain cortex. Methods: Mercuric chloride [2 mg/kg] or normal saline were injected [I.P.] to 36 Sprague – dawley rats in the 8th, 9th or 10th day of gestation. The embryos were surgically removed in the 15th day of gestation, and brain cortices were studied by histological techniques. Results: Histological studies showed that embryos of mercuric chloride treated rats hadcortical neuronal disarrangement withdifferent orientations of nuclei, increased diameter of cortex, increased mitosis of cells, increased cell death, decreased cellular density and increased intracellular space. Conclusion: These findings suggest some micro structural abnormalities in cortical regions after prenatal exposure to mercuric chloride. These structural abnormalities may underliesome neurologic disturbances following mercury intoxication

Effect of mozart husic on hippocampal content of BDNF in postnatal rats

Introduction: It has shown that listening to Mozart music can potentiate spatial tasks in human; and reduce seizure attacks in epileptic patients. A few studies have reported the effects of prenatal plus postpartum exposure of mice to the Mozart music on brain-drived neurotrophic factor [BDNF] in the hippocampus. Here we investigated the effect of postpartum exposure to The Mozart music on BDNF concentration in the hippocampus of rat. Methods: Thirty male one day old newborn Wistar rats divided randomly in two equal experimental and control groups. Experimental group exposed to slow rhythm Mozart music [Mozart Sonata for two pianos KV 448, 6 hour per day; sound pressure levels, between 80 and 100 dB] for 60 successive days. The control group was kept in separate room with housing conditions like experimental group except music exposure. After 60 days the rats were euthanized and hippocampuses extracted; then the content of BDNF protein was measured using ELISA sandwich method. Results: Data analysis revealed that rats exposed to Mozart Sonata music had significantly increased BDNF content in the hippocampus as compared to control rats [P +/- 0.01]. The concentrations of BDNF were 86.30 +/- 2.26 and 94.60 +/- 6.22 ng/g wet weight in control and music exposure groups respectively. Discussion: Exposure to the Mozart music early in life can increase the BDNF concentration in the hippocampus in rats