Influence of activator and inhibitors of Ca2+ channels on proliferative activity in Tetrahymena pyriformis infusoria

Abstract

It was determined that change in DNA content in macronuclei occurs in the T. pyriformis infuso ria under the influence of an activator (caffeine) and inhibitors of Ca 2+ channels (verapamil), NiCl 2 , and CdCl 2 . Caffeine (10 mM) stimulates DNA synthesis. Verapamil (5 µM), CdCl 2 (125 µM), and NiCl 2 (100 µM) decrease DNA content in macronuclei by 30 min after proliferative stimulation. By 4 h of incuba tion, there is, on average, 10% less DNA in macronuclei of Tetrahymena preprocessed with verapamil than in the control cells. The cells preprocessed with CdCl 2 and NiCl 2 differ from the control cells by lower DNA content almost at all studied periods, but they restore the level of nuclear DNA by 4 h. It is assumed that trans mission of proliferative signals in the T. pyriformis has a Ca 2+ dependent character.