by late 18th or early 19th century, albino rats became the most commonly used experimental animals in numerous biomedical researches, as they have been recognized as the preeminent model mammalian system. but, the precise correlation between age of laboratory rats and human is still a subject of debate. a number of studies have tried to detect these correlations in various ways. but, have not s...

background: sex steroids and their receptors exist in hippocampus and affect spatial learning and memory. this study was designed to measure testosterone level of ca1 and to assess the effect of spatial learning on its amount in left and right hippocampus of adult male rats. methods: sixteen rats were divided into two intact and castrated groups, and then trained in morris water maze (mwm). ano...

Background: Spermatozoa are germ cells that have a pivotal role at fertilisation. Infertility is a problem with a large magnitude. Sperm damages are one of the factors that cause infertility. Reactive oxygen species (ROS) like hydrogen peroxide (H2O2), superoxide anion (O2−U) or molecules and/or hydroxyl radical (UOH) affect both male and female gametes. Cyclosporine A (CsA), a neutral lipophil...

Introduction:The hippocampus is one for the major centers of learning and memory. Role of the opioid system has been investigated and on the other hand receptors related to this system such as mu-opioid receptors (MOR) are extended in the hippocampus. In this study the effect of Naloxone administration as a mu opioid receptor antagonist on passive avoidance memory in adult male rats was i...

Muricidal behavior in rats is composed of two main components, attacking and killing performance. Since a large number of mice could be killed by rats during behavioral experiments, research has been limited in the past decade possibly because of ethical considerations. In preliminary studies, we found that the rat incisors play a key role in muricidal behavior in rats, so, in the present study...