SpinalR-phenyl-isopropyl adenosine inhibits spinal dorsal horn neurons responding to noxious heat stimulation in the absence and presence of sensitizationSumida, Toshinobu*; Smith, Merton A; Maehara, Yasuhiro; Collins, G J.; Kitahata, Luke MPain: January 1998 - Volume 74 - Issue 2 - p 307–313 doi: 10.1016/S0304-3959(97)00191-7 Articles Buy Abstract Author InformationAuthors Article MetricsMetrics 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. Department of Anesthesiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA *Corresponding author. Tel.: +1 203 7852801; fax: +1 203 7375220. Submitted June 3, 1997; revised October 7, 1997; accepted October 28, 1997. © Lippincott-Raven Publishers.