جستجوی مقالات مرتبط با کلیدواژه "frontal cortex" در نشریات گروه "پزشکی"

Myelin-producing oligodendrocytes play an important role in supporting neuronal function in the mammalian nervous system. The formation of myelogenous oligodendrocytes from the ancestral oligodendrocyte cells requires the activity of a group of transcriptional regulators that are essential for the synthesis of myelin components. The aim of the present study was to investigate the effect of moderate intensity continuous training (MCT) on myelin-based protein (MBP) and myelin proteolipid (PLP) indices associated with myelination in the frontal cortex of rats.

16 male Wistar rats were randomly divided into two equal groups of control and continuous training. The exercise program consisted of 24 minutes of continuous running on a treadmill for 8 weeks (5 sessions per week). At the end of the training period, the forehead cortex of rats was extracted to evaluate changes in gene expression. Data were analyzed using statistical methods of analysis of covariance and Mann-Whitney at a significant level (α≤0.05).

The results showed that continuous training significantly increased the expression of MBP and PLP genes in comparison with the control group.

It can be said that continuous moderate intensity training can be useful in accelerating the myelination process in the cerebral cortex and can be considered as a non-invasive method in this field.

Low frequency electromagnetic waves have frequencies in the range of 300 KHz to 300 GHz and they are widely available in the environment. The biological effects of these waves are not fully understood on the human body and nervous system. The effects of low frequency electromagnetic waves on behavioural changes as well as the changes in the inner pyramidal neurons of the frontal lobe brain of the adult Wistar male rat were investigated in the present study.

In this experimental study, 20 rats were randomly divided into four groups. The first group was designated as the control group; moreover, experimental groups received 900, 1800 and 2450 MHz waves with the intensities of 2, 1 and 20 watts per kilogram, during one month and for 4 hours per day respectively. Elevated plus-maze test has been used in Behavioural tests. In addition, Golgi cox staining has been used in a hysteromorphometric test including the number of branches and dendritic spines of the inner pyramidal neurons of the frontal lobe.

In experimental groups, Eelectromagnetic waves significantly reduced the number of entry and time spent in rats in the open arms of the Elevated plus-maze test compared to the control group (p ˂ 0.05).The results of historomorphometric study also indicated a significant reduction in the number of dendritic spines and branches of the inner pyramidal neurons of the frontal lobe of the rat brain in experimental groups compared to the control group (p ˂ 0.05).   

Low-frequency electromagnetic radiation caused behavioural changes and it increased the anxiety in rats. Furthermore, it caused damage to the inner pyramidal layer neurons of the frontal cortex in experimental groups.

Recent studies have shown that oxidative stress has a critical role in the pathophysiology of Parkinson’s disease. Frontal cortex receives a great amount of dopaminergic neurons from nigrostriatal pathway and is one of the brain regions which aredamagedin Parkinson’s disease. On the other hand anti-oxidant properties of N-acetylcysteine have been proven to occur via fortifying glutathione. Glutathione is one of the main intracellular anti-oxidant systems. Therefore our study was aimed to evaluate the effect of N-acetylcysteine in the management of Parkinson’s disease. Male Wistar rats with age range of 10-12 months and weights of 400±50g received rotenone (2.5 mg/kg/48h ip) to induce Parkinson’s disease model. NAC (25 or 50 mg/kg/48h ip) was administered one hour before rotenone injections. In order to measure the motor symptoms and verify the development of the model, rotarod test was performed. Moreover the frontal cortex parkin level, one of the crucial proteins in Parkinson’s disease, was measured using western blot technique. The results indicated that N-acetylcysteine could prevent decline in the motor performance inrotarod test. In addition frontal cortex parkin level was significantly decreased in rotenone received animals while N-acetylcysteine prevented the reduction of parkin in this region. Our results indicated that that N-acetylcysteine could prevent the development of Parkinson’s disease in this model which is probably due to its anti-oxidant properties.

Cholinergic neurons of nucleus basalis magnocellularis (NBM) have a key role in learning and memory process. It has been shown that these neurons are degenerated in patients with Alzheimer disease (AD). On the other hand, using the cholinomimetic agents and acetylcholinesterase inhibitors improve cognition in these patients. Some studies have shown that the frontal cortex receives some cholinergic projections from NBM. In the present study, the effect of intrafrontal cortex administration of physostigmine (acetylcholinesterase inhibitor) was investigated on active avoidance learning on the animal model of AD. In this experimental study, NBM was lesioned electricaly in Wistar male rats, (250-300g body weight) for making the animal model of AD. Because the frontal cortex receives cholinergic projections from NBM, different doses of physostigmine (2.5, 5, 7.5 µg/µl) were injected bilaterally into the frontal cortex of lesioned rats 20 minutes before active avoidance learning (8 sessions, 30 steps in each session) in Y-maze. The results showned that active avoidance learning was decreased significantly in NBM-lesioned group. Also intrafrontal cortex injection of phsostigmine (2.5, 5, and 7.5 µg/µl) significantly severed NBM lesion-induced learning deficiency. The findings of this study suggest that the cholinergic projection of NBM to frontal cortex in lesioned animals has a negative role on this type of learning. It seems that other neurotransmitter systems such as glutamate and other afferent projections from different brain areas to frontal cortex probably are involved in this phenomenon.

Cholinergic neurons of nucleus basalis magnocellularis (NBM) have a key role in learning and memory process. It has been shown that these neurons are degenerated in patients with Alzheimer disease (AD). On the other hand, using the cholinomimetic agents and acetylcholinesterase inhibitors improve cognition in these patients. Some studies have shown that the frontal cortex receives some cholinergic projections from NBM. In the present study, the effect of intrafrontal cortex administration of physostigmine (acetylcholinesterase inhibitor) was investigated on active avoidance learning on the animal model of AD. In this experimental study, NBM was lesioned electricaly in Wistar male rats, (250-300g body weight) for making the animal model of AD. Because the frontal cortex receives cholinergic projections from NBM, different doses of physostigmine (2.5, 5, 7.5 µg/µl) were injected bilaterally into the frontal cortex of lesioned rats 20 minutes before active avoidance learning (8 sessions, 30 steps in each session) in Y-maze. The results showned that active avoidance learning was decreased significantly in NBM-lesioned group. Also intrafrontal cortex injection of phsostigmine (2.5, 5, and 7.5 µg/µl) significantly severed NBM lesion-induced learning deficiency. The findings of this study suggest that the cholinergic projection of NBM to frontal cortex in lesioned animals has a negative role on this type of learning. It seems that other neurotransmitter systems such as glutamate and other afferent projections from different brain areas to frontal cortex probably are involved in this phenomenon.