Tolerance to morphine analgesia: decreased multiplicative interaction between spinal and supraspinal sites
SC Roerig, SM O'Brien, JM Fujimoto, GL Wilcox - Brain research, 1984 - Elsevier
SC Roerig, SM O'Brien, JM Fujimoto, GL Wilcox
Brain research, 1984•ElsevierMice injected with morphine at both a supraspinal (intracerebroventricular) and a spinal
(intrathecal) site showed a multiplicative interaction between sites for the tail-flick analgesic
response. In morphine pellet-implanted mice, the decrease in this interaction was the source
of tolerance developed to subcutaneous morphine whereas the separate sites showed no
tolerance. During morphine withdrawal (after removal of the morphine pellet) synergism
between sites returned but the separate sites showed development of tolerance.
(intrathecal) site showed a multiplicative interaction between sites for the tail-flick analgesic
response. In morphine pellet-implanted mice, the decrease in this interaction was the source
of tolerance developed to subcutaneous morphine whereas the separate sites showed no
tolerance. During morphine withdrawal (after removal of the morphine pellet) synergism
between sites returned but the separate sites showed development of tolerance.
Abstract
Mice injected with morphine at both a supraspinal (intracerebroventricular)and a spinal (intrathecal) site showed a multiplicative interaction between sites for the tail-flick analgesic response. In morphine pellet-implanted mice, the decrease in this interaction was the source of tolerance developed to subcutaneous morphine whereas the separate sites showed no tolerance. During morphine withdrawal (after removal of the morphine pellet) synergism between sites returned but the separate sites showed development of tolerance.
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