Abstract |
The aim of the present study was to determine whether there is a convergence of inputs from tooth pulp (TP) and the superior sagittal sinus (SSS) on rat C1 spinal neurons, and to examine the effects of iontophoretically applied N-methyl-D: -aspartate ( NMDA) and non- NMDA receptor antagonists on the SSS-evoked activity of C1 neurons. Extracellular single unit-recordings were made from 20 C1 units responding to TP electrical stimulation with a constant temporal relationship to a digastric electromyogram signal, using a multibarrel electrode in pentobarbital-anesthetized rats. Ninety percent of C1 neurons (18/20) responding to TP stimulation also responded to the SSS stimulation. These neurons were considered to be SSS-afferent inputs from Adelta-fibers (5.8 +/- 0.6 m/s; n = 18), based on the calculation of nerve conduction velocity. After the iontophoretic application (30, 50, and 70 nA) of an NMDA receptor blocker (5R-10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cycloheptene-5,10-imine hydrogen maleate ( MK801) or a non- NMDA receptor blocker (6-cyano-7-nitroquinoxaline-2,3-dione) ( CNQX), the mean number of spikes responding to the SSS stimulation significantly decreased (30, 50, and 70 nA; P < 0.05). These results suggest that there is a convergence of inputs from SSS and TP afferents on C1 neurons; it is possible that both NMDA and non- NMDA receptors located on C1 neurons may be targets for the treatment of the trigeminal referred pain associated with migraine.
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Authors | Yoshinobu Fujimi, Mamoru Takeda, Takeshi Tanimoto, Shigeji Matsumoto |
Journal | Odontology
(Odontology)
Vol. 94
Issue 1
Pg. 22-8
(Sep 2006)
ISSN: 1618-1247 [Print] Japan |
PMID | 16998614
(Publication Type: Journal Article)
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Chemical References |
- Excitatory Amino Acid Antagonists
- Receptors, N-Methyl-D-Aspartate
- Dizocilpine Maleate
- 6-Cyano-7-nitroquinoxaline-2,3-dione
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Topics |
- 6-Cyano-7-nitroquinoxaline-2,3-dione
(pharmacology)
- Animals
- Dental Pulp
(innervation)
- Dizocilpine Maleate
(pharmacology)
- Dura Mater
(physiology)
- Electric Stimulation
- Electromyography
- Excitatory Amino Acid Antagonists
(pharmacology)
- Iontophoresis
- Male
- Neck Muscles
(innervation)
- Nociceptors
(drug effects, physiology)
- Pain, Referred
(physiopathology)
- Posterior Horn Cells
(drug effects)
- Rats
- Rats, Wistar
- Receptors, N-Methyl-D-Aspartate
(antagonists & inhibitors)
- Toothache
(physiopathology)
- Trigeminal Neuralgia
(physiopathology)
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