Effects of neonatal testosterone treatment on sex differences in formalin-induced nociceptive behavior in rats
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- Hagiwara Hiroko
- Dept. Neuroendocrinol., Yokohama City Univ. Graduate Sch. Med., Yokohama, Japan
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- Funabashi Toshiya
- Dept. Neuroendocrinol., Yokohama City Univ. Graduate Sch. Med., Yokohama, Japan
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- Kimura Fukuko
- Dept. Neuroendocrinol., Yokohama City Univ. Graduate Sch. Med., Yokohama, Japan international university of health and welfare
Bibliographic Information
- Other Title
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- ホルマリンテストに及ぼす新生仔期のテストステロン投与の影響
Description
There are sex differences in nociceptive behavior induced by formalin in rats. To determine whether these sex differences are the result of the sexual differentiation of the brain, that is masculinization and defeminization, some female rats were injected with testosterone propionate (TP, 100 mg/25 ml/rat) on the day of birth and on the following day. Other female rats and all male rats were injected with the same volume of sesame oil as controls. They were castrated at the age of 8 weeks, and implanted with a silicon tube containing 20% of 17b-estradiol or cholesterol. Two weeks after the implantation, rats were injected with 50 ml of 2% formalin in the right hind paw and their behavioral changes were observed for 1 h. In cholesterol-implanted rats, all rats exhibited 3 typical phases of pain response and there were no significant differences in the scores of nociceptive behavior. In 17b-estradiol implanted rats, female and TP-treated female rats had a significantly higher score of nociceptive behavior than male rats. These results indicate that estrogen produces sex differences in nociceptive behavior induced by formalin, and suggest that these differences are not due to the sexual differentiation of the brain, since the dose and the timing of the TP treatment effectively defeminize and masculinize female rats. Alternatively, sexual differentiation of the brain response to formalin-induced nociceptive behavior may be different from ordinary sexual differentiation. [J Physiol Sci. 2007;57 Suppl:S99]
Journal
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- Proceedings of Annual Meeting of the Physiological Society of Japan
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Proceedings of Annual Meeting of the Physiological Society of Japan 2007 (0), 099-099, 2007
PHYSIOLOGICAL SOCIETY OF JAPAN
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Details 詳細情報について
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- CRID
- 1390282680704283136
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- NII Article ID
- 130007038762
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- Data Source
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- JaLC
- CiNii Articles
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- Abstract License Flag
- Disallowed