Endogenous 5-HT inhibits firing activity of hippocampal CA1 pyramidal neurons during conditioned fear stress-induced freezing behavior through stimulating 5-HT1A receptors
✍ Scribed by Koji Tada; Kimihiro Kasamo; Tadashi Suzuki; Yamato Matsuzaki; Takuya Kojima
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 128 KB
- Volume
- 14
- Category
- Article
- ISSN
- 1050-9631
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✦ Synopsis
This study examines the activity of hippocampal CA 1 pyramidal neurons during conditioned fear stress (CFS)-induced freezing behavior in unanesthetized, unrestrained rats. The firing frequency of hippocampal CA 1 pyramidal neurons was significantly decreased when conditioned rats exhibited freezing behavior. Firing frequency returned to the baseline after freezing behavior disappeared. The selective 5-hydroxytryptamine (5-HT) 1A antagonists, N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide (WAY-100635), and N-tert-butyl-3-[4-(2-methoxyphenyl)piperazine-1-yl]-2-phenylpropamide (WAY-100135) and 5-HT depletion with parachlorophenylalanine (PCPA) completely abolished the decrease in firing frequency during CFS-induced freezing behavior. These results suggested that endogenous 5-HT inhibited the firing activity of hippocampal CA 1 pyramidal neurons during CFS-induced freezing behavior mainly through stimulating 5-HT 1A receptors.