PT - JOURNAL ARTICLE AU - C H Lee AU - B A Berkowitz TI - Calcium antagonist activity of methadone, l-acetylmethadol and l-pentazocine in the rat aortic strip. DP - 1977 Sep 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 646--653 VI - 202 IP - 3 4099 - http://jpet.aspetjournals.org/content/202/3/646.short 4100 - http://jpet.aspetjournals.org/content/202/3/646.full SO - J Pharmacol Exp Ther1977 Sep 01; 202 AB - These studies described physiologic evidence that methadone and related compounds can function as calcium antagonists. Methadone (1 X 10(-5)-1 X 10(-4) M) inhibited the contraction of the isolated rat aortic strip preparation produced by potassium chloride, norepinephrine, l-pentazocine or morphine. Methadone was most effective in diminishing aortic contractions which were highly dependent on the concentration of extracellular calcium. The d- and l-isomers of methadone were equipotent inhibitors of aortic contraction. l-Acetylmethadol (1 X 10(-6)-1 X 10(-5) M) was a potent inhibitor of vascular contraction. l-Pentazocine inhibited its own ability to contract the aorta as the dose was raised 3 X 10(-5) M. The inhibition of aortic contraction produced by methadone, l-acetylmethadol and l-pentazocine was overcome by raising the concentration of calcium in the tissue baths. The inhibition of contraction and the apparent calcium-antagonist activity of these drugs best correlates with their lipid solubility. Since calcium is a critical regulator of cellular function, the calcium-antagonist action of methadone and l-acetylmethadol may prove to be important in mediating some of their pharmacologic and toxicologic effects.