Showing 4 results for Avoidance Learning
Mahmoudreza Palizvzn, Shadi Khademi, Ali Ghazavi, Ghasem Mosayebi,
Volume 9, Issue 4 (12-2006)
Abstract
Introduction: Oxidative stress may play a critical role in neurodegenerative disorders but the relation between oxidative stress and learning ability in normal rats is not investigated, so the aim of this study was to investigate the correlation between oxidative stress and two way active avoidance learning in Wistar rats. Materials and Methods: This is an experimental research. 14 Wistar rats were assigned for assessed learning ability in shuttle box. One day after shuttle box learning, cerebrospinal fluid (CSF) and blood samples were obtained. Concentration of Nitric Oxide and Ferric reduction/antioxidant power were assessed. Data was analyzed using Pearson correlation test. Results: The results of the present study demonstrate that there are positive correlation between shuttle box learning ability and Ferric reduction/antioxidant power (p<0.001, r =0.66 4) and Nitric Oxide concentration (p<0.001, r = 0.724) in serum, but not in CSF. Conclusion: The results of this study suggest that high concentration of antioxidant power and Nitric Oxide concentration in blood can improve shuttle box learning in rats
Reza Mohajerani, Mohammad Reza Palizvan, Shahrbanou Oryan, Vahab Babapour,
Volume 11, Issue 1 (3-2008)
Abstract
Introduction: In this study the effect of extracellular trans zinc and voltage sensitive calcium channels on different aspects of learning and memory has been investigated. Materials and Methods: This is an experimental study in which the effect of a calcium channel antagonist (Verapamil) and zinc chelator (Ca-EDTA), on passive avoidance learning (shuttle box apparatus) has been examined by intraperitoneal administration of defferent doses of these drugs. Data was analyzed using one way analysis of variance. Results: Result of intraperitoneal injection of 100 milimolar Ca-EDTA indicated that it has no effect on the acquisition, consolidation, and retrieval of passive avoidance learning. Verapamil (100 and 150 micrograms) as a L-type voltage gated calcium channel antagonist, decreased acquisition and consolidation but not retrieval of passive avoidance behaviour. These effects were dose dependent. The simltaneous effect of Ca-EDTA and verapamil was also studied. Ca-EDTA (100milimolar) and verapamil (100 micrograms) have negative effects on consolidation of passive avoidance learning. Conclusion: Probably, common mechanisms are involved in acquisition and consolidation of passive avoidance learning, and zinc and calium ions play interactive roles in this aspect.
Ameneh Rezayof, Mohammad Reza Zarrindast, Niloufar Darbandi,
Volume 17, Issue 6 (9-2014)
Abstract
Background: It is well known that morphine influence learning and memory processes. The Nucleus accumbens (N.ac) which has an important role in reward participates in morphine-induced impairment of memory retention. Considering the cholinergic system is involved in the effects of morphine on learning and memory, in the present study, the effects of intra-N.ac injections of acetylcholine receptor antagonists alone or with morphine on memory retention and morphine-induced memory has been investigated in rats.
Materials and Methods: In this original research animals were bilaterally cannulated in the N.ac and a step-through passive avoidance task was used for the assessment of memory retention .
Results: Post-training subcutaneous administration of morphine dose dependently decreased the learning and induced amnesia. The administration of the same dose of morphine as pre-test treatment induced state-dependent learning. Pre-test intra- N.ac administration of atropine, scopolamine and mecamylamine in different doses alone cannot affect on memory retention. While, pretest intra- N.ac injection of these drugs before the administration of morphine dose dependently inhibited morphine state-dependent learning. The level of statistical significance was set at p<0.05 .
Conclusion: The processes of learning in animals can be affected by morphine and the opioids produce state-dependent learning. Moreover, it can be concluded that inactivation of the muscarinic and nicotinic acethylcoline receptors in the N.ac are involved in mediating morphine state-dependent learning.
Marziyeh Tavassoli, Azam Alinaghipour, Abolfazl Ardjmand,
Volume 20, Issue 6 (9-2017)
Abstract
Abstract
Background: Learning and memory are among the higher functions of the brain. State-dependent memory (STM) is a type of memory in which the recall of a learned behavior is happend only in the same sensory and physiologic condition in which the behavior is encoded. The STM is seen with some drugs, e.g. the morphine. The pentylenetetrazol (PTZ) is a durg which is used for the induction of seizure in experimental models. Some studies have been revealed different effects of the PTZ on brain higher function (learning, memory …). The aim of present study was to explore the effect of PTZ on morphine-induced STM.
Materials and Methods: In this study, male adult Wistar rats (190-220 g) were used. Animals in 3 groups (n=8) during 3 sessions (learning/memory, STM and interaction) were studied. During 48 hour (training and test) the learning and memory of animals were studied in inhibitory avoidance apparatus. The step-through latency in the test day was used as a criterion for memory. Post-training injection of saline or morphine (2.5, 5 and 7.5 mg/kg-ip) in different groups was carried out. In addition, the pre-test injection of morphine at the same doses was made to study the STM. Moreover, the interaction of pre-test single-dose PTZ (60 mg/kg-ip) on STM was studied. The locomotion of the animals was measured using the open field.
Results: The post-training injection of morphine (2.5, 5 and 7.5 mg/kg-ip) impaired the inhibitory memory of rats compared to control group (p<0.001). The post-training and pre-test injections of the same dose of morphine (7.5 mg/kg-ip) reversed the impaired memory compared to morphine (2.5 and 5 mg/kg-ip), (p<0.001). The pre-test PTZ (60 mg/kg-ip) maintained the morphine (7.5 mg/kg-ip) STM (p<0.001).
Conclusion: The present study revealed that the post-training ip injection of different doses of morphine results in the impairment of inhibitory avoidance memory in rat. In addition, the pre-test injection of the same doses of morphine reverses the impaired memory. This process is called STM. Consequently, the pre-test injection of PTZ maintains the morphine STM.
