1. Spinal R -phenyl-isopropyl adenosine inhibits spinal dorsal horn neurons responding to noxious heat stimulation in the absence and presence of sensitization
- Author
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Merton A Smith, Toshinobu Sumida, L. M. Kitahata, J. G. Collins, and Yasuhiro Maehara
- Subjects
Male ,Pain Threshold ,Adenosine ,Hot Temperature ,Vasodilator Agents ,Central nervous system ,Pharmacology ,Adenosine receptor antagonist ,Rats, Sprague-Dawley ,Theophylline ,medicine ,Noxious stimulus ,Animals ,Plant Oils ,Premovement neuronal activity ,Neurons, Afferent ,Dose-Response Relationship, Drug ,Plant Extracts ,Chemistry ,Nociceptors ,Spinal cord ,Adenosine receptor ,Rats ,Anesthesiology and Pain Medicine ,medicine.anatomical_structure ,Nociception ,Spinal Cord ,nervous system ,Neurology ,Neurology (clinical) ,Neuroscience ,Mustard Plant ,medicine.drug - Abstract
The effects of spinally administered R(−)N6-(2-phenylisopropyl) adenosine (R-PIA) on spinal dorsal horn neurons were investigated in anesthetized rats. Extracellular, single-unit recordings were measured during noxious heating of receptive fields on the hind paw. Three series of experiments were carried out to characterize the effects of R-PIA on spinal dorsal horn neuronal activity. In the first set of experiments, R-PIA dose-dependently suppressed noxiously evoked activity of spinal dorsal horn neurons. In the second set of experiments, R-PIA suppressed noxiously evoked activity in neurons sensitized by the topical application of mustard oil to a region of skin adjacent to their receptive fields. In the third set of experiments, R-PIA prevented mustard oil induced sensitization of dorsal horn neurons. In all cases, the adenosine receptor antagonist theophylline reversed the action of R-PIA. The results of these investigations indicate the involvement of spinal adenosine receptors in spinal pathways of central sensitization and in the modulation of somatically induced noxious pain.
- Published
- 1998