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Pakpoura B.,Islamic Azad University | Ahmadig S.,University of Kurdistan | Oryana S.,Islamic Azad University | Zarrindasta M.R.,Islamic Azad University | And 3 more authors.
Behavioural Pharmacology | Year: 2010

The possible involvement of N-methyl-D-aspartate (NMDA) receptors of the nucleus accumbens (NAc) in amnesia induced by scopolamine was investigated. An inhibitory (passive) avoidance task was used for memory assessment in male Wistar rats. The results revealed that intra-NAc administration of a nonselective muscarinic acetylcholine antagonist, scopolamine (1 and 2 μg/rat) impaired memory consolidation in the animals when tested 24 h later. Post-training intra-NAc administration of NMDA (0.005 and 0.01 μg/rat) also impaired memory consolidation, whereas post-training intra-NAc administration of the NMDA receptor antagonist, MK-801 (0.5, 1 and 1.5 μg/rat) did not. Intra-NAc co-administration of an ineffective dose of NMDA with ineffective doses of scopolamine (0.25 and 0.5 μg/rat) after training had no significant effect on memory consolidation, but intra-NAc injections of effective doses of NMDA (0.005 and 0.01 μg/rat) prevented the amnesic effect of an effective dose of scopolamine (2 μg/rat). In contrast, intra-NAc co-administration of MK-801 (0.5, 1 and 1.5 μg/rat) along with an effective dose of scopolamine (2 μg/rat) did not prevent the effect of the latter drug. It can be concluded that NMDA receptors in the NAc are involved in the modulation of memory consolidation that was affected by scopolamine. Behavioural Pharmacology. © 2010 Wolters Kluwer Health Lippincott Williams & Wilkins. Source


Salimpour Y.,Institute for Studies in Fundamental science IPM
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2010

A temporal point process is a stochastic time series of binary events that occurs in continuous time. In computational neuroscience, the point process is used to model neuronal spiking activity; however, estimating the model parameters from spike train is a challenging problem. The state space point process filtering theory is a new technique for the estimation of the states and parameters. In order to use the stochastic filtering theory for the states of neuronal system with the Gaussian assumption, we apply the extended Kalman filter. In this regard, the extended Kalman filtering equations are derived for the point process observation. We illustrate the new filtering algorithm by estimating the effect of visual stimulus on the spiking activity of object selective neurons from the inferior temporal cortex of macaque monkey. Based on the goodness-offit assessment, the extended Kalman filter provides more accurate state estimate than the conventional methods. Source


Zarrindast M.R.,Tehran University of Medical Sciences | Zarrindast M.R.,Institute for Studies in Fundamental science IPM | Zarrindast M.R.,Institute for Cognitive Science Studies | Ardjmand A.,Kashan University of Medical Sciences | And 2 more authors.
Archives of Iranian Medicine | Year: 2013

Backgrounds: The amnesic effect of morphine is well known in the laboratory animals. But, it is unclear that morphine at what times can exactly affect different phases of memory, including acquisition, consolidation, and retrieval. Therefore, we investigated the time profile of morphine's amnesic effect on passive (inhibitory) avoidance learning and memory in male Wistar rats. Methods: In order to evaluate the outcomes of pre- and post-training administrations of morphine, the animals were trained in a stepthrough type of passive avoidance task at various time points, and were tested 24 h after training to measure memory retrieval. Results: The results showed that acquisition of memory was impaired in the animals that received a dose of 7.5 mg/kg of morphine (Intraperitoneally) at 0, 30 min, and 1 h before training, as evidenced by a decrease in step-through latency on the test day. Post-training administrations of morphine at 30 min and 1h, 4h except for the time immediately after training, did not impair memory consolidation. The results also showed that pre-test administrations of morphine at 0 and 30 min before the test, impaired retrieval of inhibitory avoidance memory. Conclusion: Taken together, the results suggest that morphine, when injected at different time points before training, after training, or before testing affects different phases of inhibitory avoidance memory. With regard to the time of injections related to each phase, other experiments can be designed to investigate molecular mechanisms involved in the impairing effect of morphine in each phase. Source


Rezayat M.,Tehran University of Medical Sciences | Niasari H.,Tehran University of Medical Sciences | Ahmadi S.,University of Kurdistan | Parsaei L.,Tehran University of Medical Sciences | And 3 more authors.
Journal of Psychopharmacology | Year: 2010

We have previously shown lithium-induced state-dependent learning in a step-down inhibitory avoidance task. In the present study, the effects of intracerebroventricular injections of N-methyl-D-aspartate (NMDA) receptor agents on the lithium-induced state-dependent learning have been investigated. A single-trial step-down inhibitory avoidance task was used to assess memory in male Naval Medical Research Institute (NMRI) mice. The results showed that post-training lithium (10 mg/kg) decreased the step-down latency on the test day, which was reversed by pre-test administration of the same dose of the drug; indicating state-dependent learning induced by lithium. Pre-test administration of NMDA (0.0001, 0.001 and 0.01 μ/4g/mouse, intracerebroventricular) could also substitute for pre-test lithium to reverse the decrease of the step-down latency induced by post-training lithium. Furthermore, pre-test co-administration of an ineffective dose of NMDA (0.00001 μ/4g/mouse, intracerebroventricular.) with lower doses of lithium (1.25, 2.5 and 5 mg/kg, intraperitoneally.) synergistically reversed the decrease of the step-down latency. On the contrary, pre-test injections of NMDA receptor antagonist D-AP5 (0.25, 0.5, 1 and 2 μ/4g/mouse, intracerebroventricular.) disrupted state-dependent learning induced by lithium. The results suggest that NMDA receptors may be involved, at least partly, in the lithium-induced state-dependent learning. © 2010 British Association for Psychopharmacology. Source


Ahmadi S.,University of Kurdistan | Malekmohammadi N.,Tehran University of Medical Sciences | Zarrindast M.R.,Tehran University of Medical Sciences | Zarrindast M.R.,Institute for Studies in Fundamental science IPM
Archives of Iranian Medicine | Year: 2010

Background: Repeated administration of certain drugs could result in an enhancement of the behavioral effects of those drugs. In the present study, the effect of repeated administration of histamine on amnesia induced by post-training administration of the drug was examined. Methods: A single trial step-down inhibitory (passive) avoidance task was used for memory assessment in male NMRI mice. Results: The results showed that post-training administration of different doses of histamine (5, 10, and 20 fjg/mouse, i.c.v.) decreased the step-down latency on the test day. Repeated pretreatment of histamine (10 and 20 fjg/mouse) for three days followed by five days of no drug treatment prevented amnesia due to post-training histamine (20 fjg/mouse). In contrast, repeated administration of histamine H1 receptor antagonist, pyrilamine (5, 10, and 20 mg/kg) or histamine H2 receptor antagonist, ranitidine (12.5 and 25 mg/kg) 10 minutes prior to histamine injections, decreased the effect of repeated histamine administration. Moreover, a similar pattern was seen in animals which received dopamine D1 receptor antagonist, SCH 23390 (0.025, 0.5, and 1 mg/kg) or dopamine D2 receptor antagonist, sulpiride (0.2, 1, and 5 mg/kg) 10 minutes prior to histamine injections during the repeated pretreatment. Source

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