Estrogen Enhances Performance of Female Rats during Acquisition of a Radial Arm Maze

Neurobehavioral effects of dietary soy phytoestrogens

“…Increased awareness and understanding of brain plasticity (and behavior) is evolving with the advancements in technology and exchange of scientific information [2,15,18,27,33,40,43,45,47,51,62,71,78,81,96,97,104,112,114,116,123,127]. Since all commercially available rodent diets use soy as the main source of protein in their formulations, it is intriguing to consider the possible impact dietary phytoes- …”

“…This sex difference in rats has been attributed to the hormonal influence of estrogens. For example, exogenous estradiol administered to intact male rats inhibited memory, whereas estrogen replacement to ovariectomized rats enhanced memory [27,28,30,76,125]. Since estrogen hormone action appears to influence VSM, we studied the influence of phytoestrogens on VSM utilizing radial arm maze methods to examine varying aspects of memory.…”

Is there a link between adult neurogenesis and learning?

“…Conditions that increase the number of immature neurons such as estrogen (Tanapat et al, 1999), environmental complexity (Kempermann et al, 1997), and physical exercise (van Praag et al, 1999) also tend to enhance performance on hippo-campal-dependent learning tasks (Daniel et al, 1994;Kempermann et al, 1997;Luine et al, 1998;van Praag et al, 1999;Leuner et al, 2004a). Although statistical correlations are not available, it has been reported that environmental complexity and physical exercise enhance neurogenesis and learning in the same animals (Kempermann et al, 1997;van Praag et al, 1999).…”

“…Indeed, an inverse relationship between hippocampal neurogenesis and learning has been reported in the tree shrew; chronic stress diminishes the production of new neurons but appears to improve performance on a spatial navigation task (Bartolomucci et al, 2002). Similarly, although positive regulators of adult neurogenesis, such as estrogen, have been associated with enhancements in learning (Daniel et al, 1994;Luine et al, 1998;Leuner et al, 2004a), learning deficits have also been reported (Holmes et al, 2002).…”

Gene × Environment Effects: Stress and Memory Dysfunctions Caused by Stress and Gonadal Factor Irregularities during Puberty in Control And TGF-α Hypomorphic Mice

“…In fact, gonadectomy in adult male and female rodents can increase the behavioral stress response (Bernardi et al, 1989) and release of ACTH and corticosterone (Handa et al, 1994), which can be reversed by subcutaneous injection of testosterone or estradiol/progesterone (Gaskin and Kitay, 1971;Bernardi et al, 1989). Estrogen administration alone can increase basal corticosterone secretion and ACTH and corticosterone responses to physical and psychological stressors in both males and females (Burgess and Handa, 1992;Handa et al, 1994) and enhance memory performance on the radial arm maze, Tmaze, and passive avoidance conditioning (Dohanich et al, 1994;Luine and Rodriguez, 1994;Singh et al, 1994;O'Neal et al, 1996;Daniel et al, 1997;Luine et al, 1998;Sandstrom and Williams, 2001). These studies indicate that the sex differences in stress and memory processes may be partly due to the sex-dependent gonadal hormone availability in the brain even after the normal developmental milestones.…”