Neuroscience 2005 Abstract
| Presentation Number: | 861.2 |
|---|---|
| Abstract Title: | Central adrenergic receptor activation is involved in central sensitization in trigeminal subnucleus caudalis (Vc; the medullary dorn horn). |
| Authors: |
Chiang, C. Y.*1
; Xie, Y. F.1
; Zhang, S.1
; Hu, J. W.1
; Dostrovsky, J. O.2
; Sessle, B. J.1
1Dept Physiol, Univ. of Toronto, Faculty of Dentistry, Toronto, Canada 2ON, 124 Edward St, M5G1G6, |
| Primary Theme and Topics |
Neural Excitability, Synapses, and Glia: Cellular Mechanisms - Glia-neuron interactions -- Neuron-glial signaling |
| Secondary Theme and Topics | Sensory and Motor Systems<br />- Pain<br />-- Trigeminal processing |
| Session: |
861. Trigeminal Processing II Poster |
| Presentation Time: | Wednesday, November 16, 2005 9:00 AM-10:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # X33 |
| Keywords: | MECHANOSENSORY, NEUROPLASTICITY, GLIA, RAT |
Our previous studies have demonstrated that glial activation may contribute to central sensitization induced in Vc nociceptive neurons by application of the inflammatory irritant mustard oil (MO) to the tooth pulp (Chiang et al. SfN Abst 518.10, 2004; Zhang et al. SfN Abst 285.2, 2004). Since numerous noradrenergic terminals contact neurons, glia, and blood vessels in the rat spinal dorsal horn, the aim of the present study was to test for the possible involvement of central adrenergic receptor activation in Vc central sensitization. Extracellular recordings were made from nociceptive-specific (NS) neurons in the deep laminae of Vc in urethane/α-chloralose-anesthetized adult male rats. The mechanoreceptive field (RF), mechanical activation threshold and responses to graded pinch or pressure of each neuron were assessed at baseline. Then 2 assessments were made at 5 and 15 min after superfusion (0.6 ml/h throughout the experiment) onto Vc of guanethidine (sympathetic release blocker; 100 µM) or phentolamine (α-adrenergic antagonist; 300 µM) or buffered saline (as control), and MO was next applied to the maxillary first molar pulp and 5 similar assessments at 10 min intervals were made. After saline pretreatment, MO application produced prolonged and significant increases in neuronal RF size and responses to pinch/pressure and decreases in threshold (P<0.01-0.001, one-way RM ANOVA, n=6). After guanethidine or phentolamine pretreatment, the MO-induced changes were significantly attenuated (all P>0.05, one-way RM ANOVA, n=6). There were significant differences between the saline and guanethidine or phentolamine pretreatment groups in RF size, threshold and responses to mechanical stimuli (P<0.002-0.001, two-way ANOVA). These results indicate that central adrenergic receptor activation may be involved in the development of central sensitization in the dorsal horn.
Supported by NIH DE-04786
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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