Increased daily handling of ovariectomized rats enhances performance on a radial-maze task and obscures effects of estradiol replacement
Section snippets
Subjects
Forty female Long–Evans hooded rats, approximately 2 months of age, were purchased from Harlan Sprague–Dawley (Indianapolis, IN). Animal care was in accordance with guidelines set by the National Institutes of Health Guide for the Care and Use of Laboratory Animals and all procedures were approved by the Institutional Animal Care and Use Committee of Tulane University. Rats were housed individually in a temperature controlled vivarium under a 12-h light/dark cycle (lights on at 7:00 a.m.). One
Results
Data from one rat (E–SH) were excluded from all analyses due to a hormone implant lost during the acquisition trials. Data from a second rat (E–IH) were excluded from the delay-trial analyses due to a hormone implant lost during delay trials.
Discussion
The primary finding of the present study is that the enhancing effects of estradiol on working memory were obscured in rats that received 2 min of increased daily handling in addition to the standard handling that was involved in the experimental procedures and routine care. An effect of increased handling was maintained throughout the length of the experiment, which included weeks of behavioral testing. These results indicate that a minimal difference in the amount of handling that animals
Acknowledgments
This work was supported by National Science Foundation Grant 0423331 (J.M.D). We thank Amanda Bearl and Caroline Greene for their assistance in collection of behavioral data.
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2020, Frontiers in NeuroendocrinologyCitation Excerpt :Although results can vary based on sex, gonadal status, age, species, timing of treatment, and the task being used to measure memory, the balance of studies report that E2 facilitates the acquisition and/or consolidation of episodic memories in both female and male rodents (Frick, 2009; Bimonte-Nelson et al., 2010; Daniel, 2013; Luine, 2014; Tuscher et al., 2015; Hamson et al., 2016; Koss and Frick, 2017; Sheppard et al., 2018). For example, considerable research has shown that acute or chronic systemic E2 administration improves spatial memory among ovariectomized female rats and mice in traditional hippocampus-dependent tasks like the Morris water maze, radial arm maze, and T-maze, as well as in tests of object or social recognition, object location, inhibitory avoidance, and trace eyeblink conditioning (e.g., O’Neal et al., 1996; Daniel et al., 1997; Fader et al., 1998, 1999; Luine et al., 1998; Bimonte and Denenberg, 1999; Gibbs, 1999; Daniel and Dohanich, 2001; Sandstrom and Williams, 2001, 2004; Bowman et al., 2002; Heikkinen et al., 2002; Holmes et al., 2002; Garza-Meilandt et al., 2006; Bohacek and Daniel, 2007; Hammond et al., 2009; Singh et al., 1994; Frye and Rhodes, 2002; Leuner et al., 2004). Furthermore, acute systemic E2 given immediately post-training to ovariectomized rats and mice enhances memory consolidation in the Morris water maze and object recognition tasks (e.g., Luine et al., 2003; Gresack and Frick, 2006; Walf et al., 2006; Frye et al., 2007; Fernandez et al., 2008; Inagaki et al., 2010).
Tactile stimulation of adult rats modulates hormonal responses, depression-like behaviors, and memory impairment induced by chronic mild stress: Role of angiotensin II
2020, Behavioural Brain ResearchCitation Excerpt :Receiving affectionate touch has been shown to attenuate stress reactivity during specific stressful experiences [91]. Similar results were found in rodents, where different tests showed that tactile stimulation of adult rats reduced the anxiety in different tests [17–19], seemed to improve memory [19,20], reduced blood pressure and heart rate [92], decreased adrenal catecholamine secretion [46], increased spinal cord blood flow [93], increased brain dopamine release [45] and enhanced the release of endogenous opioids [94]. In rabbits and dogs, the use of touch reduced stress and fear in adult animals [95,96].