background several studies showed that dopamine and norepinephrine improve retention and retrieval of memory. methylphenidate is an enhancer of dopamine and norepinephrine in brain. objectives in the present study, the effect of methylphenidate was evaluated on retention and retrieval of memory in young and aged mice using passive avoidance apparatus. materials and methods animals were divided ...

the central cholinergic system has been associated with cognitive function and memory and acetylcholine plays an important role during the early stages of memory consolidation. in this study, after training mice were tested with one way active avoidance procedure and retention were tested at 4, 8, 12, 16 and 24 hours of training and compared with non-shocked mice, in which it took 24 hours, a s...

many factors are involved in learning and memory processes including brain nuclei, neurotransmitter systems, and the activity of ion channels. studies showed inconsistent effects of calcium channel blockers on learning process, especially memory consolidation; however, little is known about their effect on memory acquisition and retrieval. accordingly, the present study aimed to determine the e...

Background and Objective: It is well known that stress and glucocorticoid, modulate memory processing, though the result is completely dependent on the time of stress induction. This study investigated the effect of acute corticosterone administration on memory retrieval of recent and remote memory in a 4 trials/day (low- intensity learning) or 8 trials/ day (high- intensity learning) Morris wa...

background sildenafil (viagra) has been introduced to treat erectile dysfunction by acting as phosphodiesterase 5 inhibitor and hence accumulation of guanosine cyclic monophosphate (cgmp). on the other hands, the nitric oxide/cgmp signaling pathway has crucial role in synaptic plasticity processes like long-term potentiation (ltp) in the central nervous system considered as a model of learning ...

objective : in this study, the effects of estradiol valerate and raloxifenea selective estrogen receptor modulator; (serm) on morphine induced sensitization were examined in mice memory, according to the step-down passive avoidance task. method: the mice received morphine or estradiol and raloxifene for three days alone or in combination with morphine. after a drug free period of 5 days, the su...

objective: strong evidence indicate that activity of glucocorticoid receptors is necessary for emotional memory processess and these effects probably are mediated by hipppocampal opioid receptors. the aim of this study was to test whether there were any interaction between glucocorticoid and hippocampal opiate receptors on consolidtaion and retrieval of spatial memory. materials and methods: in...

objective(s): due to the prevalence and pervasiveness of stress in modern life and exposure to both chronic and acute stresses, it is not clear whether prior exposure to chronic stress can influence the impairing effects of acute stress on memory retrieval. this issue was tested in this study. materials and methods: adult male wistar rats were randomly assigned to the following groups: control,...