Testosterone modulates spatial recognition memory in male rats

• Published in: Hormones and behavior 2013-04, Vol.63 (4), p.559-565
• Main Authors: Hawley, Wayne R., Grissom, Elin M., Martin, Ryan C., Halmos, Miklos B., Bart, Corrine L.S., Dohanich, Gary P.
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Animal cognition; Animal memory; Animals; Behavioral psychophysiology; Biological and medical sciences; Body weight; Fundamental and applied biological sciences. Psychology; Hormones and behavior; Ischiocavernosus muscle; Male; Maze Learning - drug effects; Memory - drug effects; Orchiectomy; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Long-Evans; Recognition (Psychology) - drug effects; Rodents; Space Perception - drug effects; Spatial recognition memory; Testosterone; Testosterone - pharmacology; Weight Gain - physiology
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2013.02.007

A growing body of research indicates that testosterone influences spatial cognition in male rats; however, the overwhelming majority of studies have been conducted on tasks motivated by either food deprivation or water escape. The hippocampus-dependent version of the Y-maze task, which characterizes spatial recognition memory, capitalizes on the propensity of rats to gravitate toward novel spatial environments and is not contingent upon either appetite or the stress associated with water escape, two factors also affected by testosterone. Accordingly, the aim of the current study was to examine the effects of orchidectomy and subsequent testosterone treatment on spatial recognition memory. Orchidectomy did not impact spatial recognition memory when the delay between the information and retention trials of the Y-maze task was 24h. Alternatively, on the second Y-maze task, which featured a 48-h delay between trials, orchidectomy reduced, and treatments that produced higher levels of testosterone restored, preference for the arm associated with the novel spatial environment. Importantly, there were no differences in activity levels as a function of orchidectomy or testosterone treatment on either of the two tasks. Consistent with previous findings, orchidectomy attenuated, and testosterone treatment restored, both body weight gain and the relative weight of the androgen-sensitive ischiocavernosus muscle, which confirmed the efficacy of orchidectomy and testosterone treatments on physiological outcomes. Therefore, testosterone influenced spatial cognition on a task that minimized the influence of non-mnemonic factors and took advantage of the innate preference of rodents to seek out novel spatial environments. ► Orchidectomy impaired spatial recognition memory. ► Testosterone treatment reversed the orchidectomy-induced deficit in spatial memory. ► Orchidectomy attenuated body weight gain, an effect reversed by testosterone. ► Testosterone prevented orchidectomy-induced atrophy of ischiocavernosus muscle.