Journal article
Inhibition and facilitation of different nocifensor reflexes by spatially remote noxious stimuli
Journal of neurophysiology, Vol.72(3), pp.1152-1160
09/1994
Handle:
https://hdl.handle.net/2376/114518
PMID: 7807200
Abstract
1. Noxious stimuli have been shown to produce a diffuse inhibition of nociresponsive neurons in the spinal and trigeminal dorsal horns. The present study sought to extend these electrophysiological studies of diffuse noxious inhibitory controls (DNIC) by determining the effect of a spatially remote noxious stimulus on behavioral measures of nociception. Changes in latency for hindpaw withdrawal and tail flick reflexes were measured in lightly halothane-anesthetized or awake, spinally transected rats before, during, and after application of a spatially remote noxious stimulus. 2. Surprisingly, in no case did application of a spatially remote noxious stimulus inhibit the hindpaw withdrawal reflex. The latency for this reflex was either reduced or did not change when the tail or contralateral hindpaw was placed in hot water (50 degrees C) or when a noxious pinch was applied to the ear. In contrast, the latency for the tail flick reflex was consistently increased when the hindpaw was placed in hot water. Both the hindpaw reflex facilitation and the tail flick reflex inhibition produced by a noxious conditioning stimulus were attenuated in spinally transected rats indicating supraspinal modulation of both reflexes. 3. In addition, and consistent with the work of others, placing the tail in hot water reduced the evoked activity of convergent neurons in both the trigeminal and lumbar spinal dorsal horns. Thus inhibition of the activity of nociresponsive neurons in the dorsal horn is consistent with inhibition of the tail flick reflex, but not with facilitation of the hindpaw withdrawal reflex.
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Details
- Title
- Inhibition and facilitation of different nocifensor reflexes by spatially remote noxious stimuli
- Creators
- M M Morgan - Department of Psychology, Washington State University, Vancouver 98663M M HeinricherH L Fields
- Publication Details
- Journal of neurophysiology, Vol.72(3), pp.1152-1160
- Academic Unit
- Psychology, Department of
- Publisher
- United States
- Grant note
- DA-01949 / NIDA NIH HHS DA-05399 / NIDA NIH HHS
- Identifiers
- 99900547504701842
- Language
- English
- Resource Type
- Journal article