Research ArticleNEUROPHARMACOLOGY
Acute Antinociceptive Tolerance and Asymmetric Cross-Tolerance between Endomorphin-1 and Endomorphin-2 Given Intracerebroventricularly in the Mouse
Hsiang-en Wu, Kuei-chun Hung, Hirokazu Mizoguchi, James M. Fujimoto and Leon F. Tseng
Journal of Pharmacology and Experimental Therapeutics December 2001, 299 (3) 1120-1125;