Neuroscience 2003 Abstract
| Presentation Number: | 186.16 |
|---|---|
| Abstract Title: | Pathways mediating pad of sensory afferents in the mouse spinal cord <I>in vitro</I>. |
| Authors: |
García, A.*1
; Quevedo, J. N.1
1Physiology, Biophysics and Neurosci., CINVESTAV, Mexico City, Mexico |
| Primary Theme and Topics |
Motor Systems - Spinal Cord -- Reflexes |
| Session: |
186. Spinal Reflexes Poster |
| Presentation Time: | Sunday, November 9, 2003 11:00 AM-12:00 PM |
| Location: | Morial Convention Center - Hall F-I, Board # I98 |
| Keywords: | SPINAL CORD, REFLEX |
We have studied in the in vitro spinal cord preparation of juvenile mice (P7-10) with intact brainstem and hindlimb peripheral nerves the organization of pathways mediating primary afferent depolarization (PAD) of sensory afferents. PAD was inferred from dorsal root potentials (DRPs) elicited by stimulation of low threshold sensory afferents, and recorded from ipsilateral L3-L5 dorsal roots. Spatial facilitation between DRPs produced by stimulation of two selective hindlimb nerves was taken as an evidence of convergence in common pathways underlying PAD (Brink et al. J. Neurophysiol. 51:432, 1984). As in juvenile mice PAD is produced by activation of low threshold flexor and cutaneous afferents (Garcia & Quevedo, SFN abstr. 4766, 2001), interactions between DRPs evoked by stimulation of flexor (PBSt and DP) and cutaneous (CCS and SP) nerves with single shocks (1.2-2T and intervals of 0 ms) were examined. In all the tested combinations: cutaneous+flexor (CCS+PBSt and CCS+DP), flexor+flexor (PBSt+DP) and cutaneous+cutaneous (CCS+SP), either spatial facilitation or occlusion were found, although between flexor+flexor (PBSt+DP) a lack of convergence (linear summation) was the predominant effect. These results suggest that similarly to adult cats, in juvenile mice there is a great extent of convergence of afferent inputs on pathways mediating PAD of low threshold sensory afferents. We assumed that DRPs evoked by stimulation of cutaneous and muscle nerves were produced mainly by depolarization of low threshold cutaneous and group I muscle afferents. To disclose further the organization of pathways mediating PAD in juvenile mice, we will explore excitability changes using Wall’s technique and selective activation of muscle spindle afferents by muscle stretch.
Supported by Consejo Nacional de Ciencia y Tecnología, México.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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