Abstract

The effects of stimulation of the thalamic sensory relay nucleus (TSRN, nucleus ventralis posteromedialis) on the jaw-opening reflex (JOR) in response to tooth pulp stimulation were compared with the effects of stimulation of the periaqueductal gray (PAG) and nucleus raphe magnus (NRM) in the cat. After stimulation of the TSRN, PAG and NRM, the JOR was inhibited. However, while the inhibitory effects of PAG and NRM stimulation lasted for more than 500 ms and were antagonized by the opiate antagonist, naloxone, the inhibitory effects of TSRN stimulation lasted for approximately 100 ms and were resistant to naloxone. These findings suggest that although TSRN stimulation exerts descending inhibitory effects on segmental nociceptive activity, similarly to PAG or NRM stimulation, the descending inhibitory pathways mediating the effect of TSRN stimulation may be largely distinct physiologically as well as pharmacologically from those mediating the effect of PAG and NRM stimulation.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.