Noradrenaline inhibits the programmed cell death induced by 1,25-dihydroxyvitamin D-3 in glioma

The rat glioma cell line C6.9 has been recently reported to respond to 1,25-dihydroxyvitamin D-3 (1,25(OH)(2)D-3) by the induction of a programmed cell death. Since, in vivo, glial cells are thought to be exposed to several neurotransmitters, we investigated the possibility of a neurotransmitter-mediated inhibition of this active cell death process. Noradrenaline and the beta-adrenoceptor agonist isoproterenol showed significant inhibition of the 1,25(OH)(2)D-3-induced programmed cell death. The beta-adrenoceptor antagonist propanolol reversed this inhibition, while the alpha-adrenoceptor antagonist yohimbin was devoid of any effect. This suggests that the efficiency of antiproliferative vitamin D-related therapies could be influenced by endogenous levels of noradrenaline.