Differential Effects of Neurokinin-1 Receptor Activation in Subregions of the Periaqueductal Gray Matter on Conditional and Unconditional Fear Behaviors in Rats
Abstract
Central neurokinin-1 (NK-1) receptors are thought to modulate aversion, whereas the periaqueductal gray matter (PAG) is a common pathway for the integration of fear behaviors. The authors determined whether injection of an NK-1 agonist (GR73632) into subregions of the PAG would alter fear-related behaviors. Behavioral inactivity was increased by GR73632 injected into the caudodorsal PAG or the dorsal raphe. Flight behavior induced by stimulation of the dorsal PAG or by a footshock was decreased after injection of GR73632 into the dorsal PAG. Rats that had 6 pairings of a tone with a footshock after injection of GR73632 into the dorsal PAG displayed more freezing behavior than controls at the beginning of the session. However, there was no change in the shock- or the tone-induced freezing because some GR73632-treated rats, but no controls, froze during the baseline period. It is concluded that NK-1 receptors in the dorsal PAG modulate the unconditional but not the mnemonic aspects of fear behaviors.
Additional Information
© 1998 American Psychological Association. Received October 31, 1997. Revision received March 6, 1998. Accepted April 23, 1998. Research at Nottingham University was supported by a fellowship from the Human Frontier Science Program, and research at UCLA was supported by National Science Foundation Grant IBN-9723295. We would like to thank Glaxo Research and Development, Stevenage, England, for their gift of the NK-1 antagonist GR203040.Additional details
- Eprint ID
- 46513
- Resolver ID
- CaltechAUTHORS:20140625-143317559
- Human Frontier Science Program
- IBN-9723295
- NSF
- GR203040
- Glaxo Research and Development, Stevenage, England
- Created
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2014-06-25Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field