RT Journal Article SR Electronic T1 Studies on the direct spinal action of narcotics in the production of analgesia in the rat. JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 411 OP 428 VO 202 IS 2 A1 T L Yaksh A1 T A Rudy YR 1977 UL http://jpet.aspetjournals.org/content/202/2/411.abstract AB