The synthetic kappa-opioid agonist (-)U50,488 does not affect calcium transport into R1.1 mouse thymoma cell line

In this paper, the effect of the synthetic kappa-opioid agonist (-)U50,488 on 45Ca2- transport into R1.1 mouse thymoma cells is presented. This thymoma cell line expresses selectively the kappa-opioid class of receptors. 45Ca2+ transport into R1.1 cells was not affected by the kappa-opioid agonist (-)U50,488 (10(-10) M-10(-4) M) alone, or in the presence of the plant lectins: PHA (250 microg/ml) and Con A (800 microg/ml), after a 60 min treatment. The plant lectins PHA and Con A stimulated 45Ca2+ transport into R1.1 cells, in high concentrations (100-800 microg/ml) and (200-1000 microg/ml) respectively, after a 60 min treatment. Thus, 45Ca2+ transport was not affected in R1.1 cells by the kappa-opioid agonist (-)U50,488 alone, or in the presence of mitogens after a 60 min treatment. This negative result does not indicate the lack of calcium channels on R1.1 cells, since the plant lectins PHA and Con A were able to stimulate 45Ca2+ transport into R1.1 cells.