Ovariectomy results in variable changes in nociception, mood and depression in adult female rats

Decline in the ovarian hormones with menopause may influence somatosensory, cognitive, and affective processing. The present study investigated whether hormonal depletion alters the nociceptive, depressive-like and learning behaviors in experimental rats after ovariectomy (OVX), a common method to d...

Full description

Saved in:

Bibliographic Details
Published in:	PloS one 2014-04, Vol.9 (4), p.e94312
Main Authors:	Li, Li-Hong, Wang, Zhe-Chen, Yu, Jin, Zhang, Yu-Qiu
Format:	Article
Language:	eng
Subjects:	Affect - drug effects Analysis Animals Behavior Behavior, Animal Biology and Life Sciences Biting Care and treatment Cognitive ability Conditioning Depression - etiology Depression - physiopathology Depression, Mental Diagnosis Dilution Estrogens Fear - drug effects Female Females Footshock Formaldehyde Formaldehyde - pharmacology Health aspects Hormone replacement therapy Hormones Hyperalgesia Hyperalgesia - physiopathology Hyperalgesia - psychology Hypersensitivity Information processing Laboratory animals Maze Learning Medical research Medicine and Health Sciences Memory Menopause Mental depression Methods Mood Neuralgia - chemically induced Neuralgia - physiopathology Neuralgia - psychology Neurobiology Neurosciences Nociception - drug effects Ovariectomy Ovariectomy - adverse effects Pain Pain perception Rats Rats, Sprague-Dawley Risk factors Rodents Sciatic nerve Spatial discrimination learning Surgery Swimming
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Decline in the ovarian hormones with menopause may influence somatosensory, cognitive, and affective processing. The present study investigated whether hormonal depletion alters the nociceptive, depressive-like and learning behaviors in experimental rats after ovariectomy (OVX), a common method to deplete animals of their gonadal hormones. OVX rats developed thermal hyperalgesia in proximal and distal tail that was established 2 weeks after OVX and lasted the 7 weeks of the experiment. A robust mechanical allodynia was also occurred at 5 weeks after OVX. In the 5th week after OVX, dilute formalin (5%)-induced nociceptive responses (such as elevating and licking or biting) during the second phase were significantly increased as compared to intact and sham-OVX females. However, chronic constriction injury (CCI) of the sciatic nerve-induced mechanical allodynia did not differ as hormonal status (e.g. OVX and ovarian intact). Using formalin-induced conditioned place avoidance (F-CPA), which is believed to reflect the pain-related negative emotion, we further found that OVX significantly attenuated F-CPA scores but did not alter electric foot-shock-induced CPA (S-CPA). In the open field and forced swimming test, there was an increase in depressive-like behaviors in OVX rats. There was no detectable impairment of spatial performance by Morris water maze task in OVX rats up to 5 weeks after surgery. Estrogen replacement retrieved OVX-induced nociceptive hypersensitivity and depressive-like behaviors. This is the first study to investigate the impacts of ovarian removal on nociceptive perception, negative emotion, depressive-like behaviors and spatial learning in adult female rats in a uniform and standard way.
ISSN:	1932-6203 1932-6203