title: Oral exposure to low-dose of nonylphenol impairs memory performance in Sprague-Dawley rats.
abstract: Nonylphenol ethoxylate (NPE) is a non-ionic surfactant, that is degraded to short-chain NPE and 4-nonylphenol (NP) by bacteria in the environment. NP, one of the most common environmental endocrine disruptors, exhibits weak estrogen-like activity. In this study, we investigated whether oral administration of NP (at 0.5 and 5 mg/kg doses) affects spatial learning and memory, general activity, emotionality, and fear-motivated learning and memory in male and female Sprague-Dawley (SD) rats. SD rats of both sexes were evaluated using a battery of behavioral tests, including an appetite-motivated maze test (MAZE test) that was used to assess spatial learning and memory. In the MAZE test, the time required to reach the reward in male rats treated with 0.5 mg/kg NP group and female rats administered 5 mg/kg NP was significantly longer than that for control animals of the corresponding sex. In other behavioral tests, no significant differences were observed between the control group and either of the NP-treated groups of male rats. In female rats, inner and ambulation values for animals administered 0.5 mg/kg NP were significantly higher than those measured in control animals in open-field test, while the latency in the group treated with 5 mg/kg NP was significantly shorter compared to the control group in step-through passive avoidance test. This study indicates that oral administration of a low-dose of NP slightly impairs spatial learning and memory performance in male and female rats, and alters emotionality and fear-motivated learning and memory in female rats only.
authors.affiliation: Graduate School of Science and Technology, Nagasaki University.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kawaguchi
authors.forename: Rika
authors.initials: R
authors.lastname: Kuwahara
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kohara
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Uchida
authors.forename: Yushi
authors.initials: Y
authors.lastname: Oku
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Yamashita
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D001522:Behavior, Animal / Q000187:drug effects*; D004644:Emotions / Q000187:drug effects; D052244:Endocrine Disruptors / Q000008:administration & dosage / Q000633:toxicity*; D005239:Fear / Q000187:drug effects; D005260:Female; D008297:Male; D008568:Memory / Q000187:drug effects*; D010636:Phenols / Q000008:administration & dosage* / Q000633:toxicity*; D011597:Psychomotor Performance / Q000187:drug effects*; D017207:Rats, Sprague-Dawley; D065853:Spatial Learning / Q000187:drug effects*; D013501:Surface-Active Agents / Q000008:administration & dosage* / Q000633:toxicity*; D016138:Walking
chemical_list: D052244:Endocrine Disruptors; D010636:Phenols; D013501:Surface-Active Agents; C025256:nonylphenol