Abstract
The physiological and pharmacological properties of two classes of putative nociceptive modulatory neurons have been extensively characterized in the rostral ventromedial medulla (RVM) of the barbiturate-anesthetized rat. 'On-cells' show a burst of activity, and 'off-cells' a sudden pause immediately preceding the occurence of nocifensor reflexes. In the present study, we have characterized the reflex-related activity of RVM neurons in halothane-anesthetized rats to determine whether the properties of these neurons are dependent on barbiturate anesthesia. Both on- and off-cells were identified in this preparation. Repeated noxious stimulation was associated with a high level of ongoing activity in on-cells, and a low level in off-cells. These data thus demonstrate that the previously described reflex-related changes in RVM neuron activity are not specific to barbiturate-anesthetized preparations, and that a failure to demonstrate off-cells in some studies may result from these neurons being inactive following repeated testing with noxious stimuli.
Original language | English (US) |
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Pages (from-to) | 154-158 |
Number of pages | 5 |
Journal | Brain research |
Volume | 582 |
Issue number | 1 |
DOIs | |
State | Published - Jun 5 1992 |
Externally published | Yes |
Keywords
- Barbiturate
- Nociception
- Nucleus raphe magnus
- Pain modulation
- Tail flick
- γ-Aminobutyric acid
ASJC Scopus subject areas
- General Neuroscience
- Molecular Biology
- Clinical Neurology
- Developmental Biology