جستجوی مقالات مرتبط با کلیدواژه « synapses » در نشریات گروه « پزشکی »

As previous studies show, several effects of morphine are induced by the dopaminergic system. Sulpiride is a dopamine D2 receptor (DAD2) antagonist widely used in clinics to treat DArelated disorders. DAD2 receptors are abundant at hippocampal cornu ammonis (CA1).

This study aimed to investigate the possible interaction of morphine and sulpiride on DA synapses in CA1.

In this study, 48 Wistar rats weighing 220 to 250 g were used. These animals were classified into eight groups (6 rats per group): saline control group (1 ml/kg), morphine group (5 mg/kg), sulpiride groups alone (1, 2, and 4 mg/kg) and sulpiride groups (1, 2, and 4 mg/ kg)+morphine (5 mg/kg). Saline or substances were injected once intraperitoneally. After 48 h, the animals’ brains were removed under anesthesia and placed in 10% formalin for fixation. Then, 3- to 4-μm slices were cut from these tissues, and the DA synapse was examined by histochemistry and immunohistochemistry techniques. The data were statistically analyzed by the analysis of variance.

The control group had DA synapses and healthy neurons. A relative increase in DA synapses compared to the control group was observed in the morphine and single sulpiride groups. However, in sulpiride+morphine groups, DA synapses were reduced compared to morphine or sulpiride alone, but neurons were not destroyed.

The interaction effect of sulpiride and morphine in the CA1 region may decrease DA synapses.

The application of radar systems in telecommunications and aerospace science is important. However, engineering department’s staff various tissues are always under chronic radiation generated by the radar fields which may affect health. This study aims to evaluate the risk of radar wave exposure and to explore the effects and limitations. In this simulation study, an adult body model versus 1 watt source with a distance of 50 centimeters exposure has been simulated using the CST STUDIO SUITE. Furthermore, various physical and electrical properties of each tissue and organ for different frequencies and exposure times have been studied. The exposure dose limitations have been considered using the International Commission on Non-Ionizing Radiation Protection (ICNIRP) safety and health guide report. Total body absorbed doses for 4 GHz, 8 GHz, and 12 GHz frequency, and 6 min, 4 h, and 30 days exposure time, have been calculated as 1.136×10-5, 1.598×10-5, 1.58×10-3, 1.521×10-5, 3.122×10-5, 4.52×10-3, 4.1×10-5, 10-4, and 10-2, respectively. It has shown that the internal organs of the body and head will be under more risk by reducing radar frequencies from 12 GHz to 4 GHz. On the other hand, the higher frequency can cause a higher risk to the human skin. In addition, the maximum Specific Absorption Rate (SAR) for each case has been calculated. The results show that for this normalized source, the safety criteria have been respected, but for a higher source, the calculations must be repeated.

Gadolinium (Gd3+) is a chemical element belonging to the lanthanide group and commonly used in magnetic resonance imaging (MRI) as a contrast agent. However, recently, gadolinium has been reported deposition in the body after a patient receives multiple injections. Gadolinium is a potent block and competes with calcium diffusion into the presynaptic. There has not been a precise mechanism of gadolinium blocking calcium channel as a channel of calcium diffusion to presynaptic until now.

This study aims to investigate the mechanism of calcium influx model and the effect of neurotransmitter release to the synaptic cleft influenced by the presence of Gd3+.

Monte Carlo Cell simulation was used to analyze simulation and also Blender was used to create and visualize the model for synapse. The synapse modeled by a form resembling the actual synapse base on a spherical shape.

The presence of gadolinium around the presynaptic has been disturbing diffusion of calcium influx presynaptic. The result shows that the presence of gadolinium around the presynaptic has caused a decrease in the amount of calcium influx presynaptic. These factors contribute to reducing the establishment of the active membrane, then the amount of synaptic vesicle docking and finally the amount of released neurotransmitter.

Gadolinium and calcium compete with each other across of calcium channel. The presence of gadolinium has caused a chain effect for signal transmission at the chemical synapse, reducing the amount of active membrane, synaptic vesicle docking, and releasing neurotransmitter.

Autism spectrum disorder (ASD) is a complex, heterogeneous neurodevelopmental disorder with onset during early childhood. Most studies have reported an elevation in platelet serotonin in persons with autism. The serotonin (5-hydroxytryptamine; 5-HT) transporter in the brain uptakes 5-HT from extracellular spaces. It is also present in platelets, where it takes up 5-HT from plasma. Polymorphisms in serotonin transporter gene (SLC6A4) were frequently studied in many neuropsychiatric disorders.

We have measured the plasma 5-HT levels in 20 autistic male children and 20 control male children by the enzyme-linked immunosorbent assay (ELISA) method. In addition, the SLC6A4 promoter region (5-HTTLPR) insertion/deletion (I/D) polymorphism was studied, using whole genomic DNA.

Plasma serotonin was significantly low in autistic children compared to control (P = 0.001), although correlation to severity of autism was not significant. The frequency of short (S) allele in autism cases was 10% and in the control group it was absent.

Our study demonstrated an increased prevalence of 5-HTTLPR S allele in autism subjects. Significantly decreased plasma serotonin was detected in autism subjects, with no significant relationship between 5-HTTLPR genotype and plasma 5-HT being evident.