Introduction: Parkinson"s disease (PD) is a human neurodegenerative disorder which is associated with a massive and progressive degeneration of dopaminergic neurons in subistantia nigra (SN). There is a strong evidence of an oxidative stress participates in the etiology of PD. Materials and Methods: The rats were divided into sham-operated, experimental and vitamin E-treated groups. For anesthesia, a mixture of ketamine and xylazine was used (i.p.). The experimental group received 5ml of 0.9% saline containing 6-hydroxydoppamine (6-OHDA) and 2% ascorbic acid in addition to 0.8 ml/kg of propylene glycol (PG, i.m.), and sham-operated group received and identical volume of saline- ascorbate in left side of striatum. The vitamin E-treated group received D-a-tocopheryl acid succinate (24 I.U./Kg, i.m.) dissolved in PG, one hour before the surgery and three times a week for a month after the surgery. Tyrosine hydroxylase (TH) immunohistochemistry in SN and striatum was used as an index for the tratment efficacy. Results: The results, showed than an over all reduction (47%) in the number of TH immunoreactive (IR) neurons in the left SN-cell was observed in 6-OHDA lesioned group (P<0.005). However, the cell loss had attenuated to 18% in vitamin E-treated animals (P<0.05) compared with the right side. A non-significant difference in the number of TH-positive neurons between the sham-operated and the vitamin E-treated groups was noticed. A microscopic inspection of the injection site in the striatum revealed that in all treated animal, there was a dense halo of TH-IR fiber around the needle track. A grater loss of TH-IR fiber has been observed around the injection site in the experimental group. Conclusion: Vitamin E-treatment can enhance the resistance and longitivity of dopaminergic nigral neurons against the oxidative stress induced by 6-OHDA. The results may prompt an interest in the use of vitamin E as a neuroprotective agent in the treatment of PD.

Introduction: Nigrothalamocortical tract is one of the main outputs of the basal nuclei, but its role in motor disturbances is vauge, because there is little informations on its connection structure. Some electrophysiological and pharmacological surveys report that none-dopaminergic outputs originate from reticular part of substantia nigra and end at thalamus. In this study the topographical connection of substantia nigra with thalamus was studied using HRP tracer. Materials and Methods: A tracer, stereotaxically was injected into the MD nucleus of thalamus of 25 rats. The animals were perfused transcardially 48-72 hours later, and the brain tissue was fixed. 40-50 micrometer sections were prepared from diencephalon and midbrain. Following enzymatic reactions, the sections were stained by Tetramethyl-Benzidin method. Results: The light microscopic study showed that there is a high concentration of neurons which were projected to the MD nucleus in the rostro lateral parts of pars reticulata (SNR) and the number of labeled cells decrease in the caudal parts. Other labeled neurons are located at the border of SNC, SNR and VTA, specially close to the passage of III cranial nerve. In general, the size of neurons was small, medium; and multipolar in shape labeled. We didn"t see any labeled cell in the substantia nigra opposite to injection site. Conclusion: Our findings shows that none-dopaminergic efferents which originate from substantia nigra nuclei and terminate in MD nucleus. It seems that these fibers not only affect motor mechanisms, but also influence the limbic system and sensory functions.

Introduction: The effectiveness of θ-pattern primed-burst (PBs) for the induction of long-term potentiation (LTP) of population excitatory postsynaptic potential (pEPSP) and population spikes (PS) were investigated in hippocampal CA1 of pentylenetetrazol-kindled rats. Materials and Methods: Experiments were carried out in the control and kindled animals. Field potentials (pEPSP and PS) were recorded at stratum radiatum and stratum pyramidale following stimulation of the stratum fibers, respectively. PBs was delivered to stratum fibers and PB potentiation was assessed. Results: The results showed that 48-144 h after kindling PB potentiation in stratum radiatum of kindled animals was not significantly changed compared to controls. In stratum pyramidale PBs induced LTP in control animals but not in kindled ones. Conclusion: The effect is compatible with the hypothesis that postulate kindling associated functional deficit in hippocampus, especially CA1, as an explanation for the behavioral deficits seen with the kindling model of epilepsy.      

There is a relationship between a neuron's response pattern (PSTH: peristimulus time histogram) and its physiological functions. Since, the PSTH types of the neurons of the inferior colliculus were not well established, this study was performed in anesthetized guinea pigs, using extra cellular recording technique, to identify and categorize the response patterns of collicular neurons. The responses of 216 neurons to pure tones presented at the best frequency to the. contralateral ear, were collected and PSTH was produced for each unit. The temporal response patterns were divided to six main PSTH types as followings: 1-onset; 2-pausey, 3- on-sustained; 4-chopper; 5-sustained and 6-off. These patterns were further divided to subgroups and the possible mechanisms of the responses as well as their functional implications were discussed.

Haloperidol is a neuroleptic drng used for the treatment of Psychiatric disorders and agitation. The main effectiveness of the drng is occurred by blocking dopamin receptor in neural system. In 1990 Jurand was applied 30 mg/Kg haloperidol on the 8th gestation day in mouse. It was revealed dilatation in Fourth ventricle brain and ectopic neural tube was occured.In this study the effectiveness of haloperidol was assessed in two groups of animal. In the first group, 5 mg and in the second group 10 mg/Kg of drng was administered by intraperitoneal in 8th day of gestation. The embryos were taken from uters and processed using paraffin embedded and patin and methods. The slides were studied under light microscope.The results were indicated that, There was a significant relation between applying haloperidol and opening of primary neural tube (P>0.05). In addition malformation in secondary neural tube like opening or absence of neural tube was observed.