Gustafsson L L, Post C
Acta Pharmacol Toxicol (Copenh). 1986 Apr;58(4):243-8. doi: 10.1111/j.1600-0773.1986.tb00102.x.
Antinociceptive effects of intrathecal injections of morphine and pethidine were evaluated in rats using the hot-plate and tail-flick tests. Both drugs elicited antinociceptive effects either it was evaluated with maximal response latency (sec.) or with area under the curve (AUC) (sec. X min.). The effects of pethidine were shortlived. The concentration of morphine in the spinal cord correlated to its antinociceptive effects when tested on hot plate. A minimal morphine concentration of 3 pmol/mg in the spinal cord was required to induce experimental analgesia in the rat.
