Living cells control their electrical responsiveness by regulating the quality and quantity of channels expressed in the plasma membrane. Regulation of transcription of the voltage-gated ion channels is an important part of the molecular basis of cell energization. However, the factors which control the expression of channels are not well understood. We studied the effect on the transcription of the voltage-gated K(+) channel in the yeastSchizosaccharomyces pombe of cations, pH, and therapeutic spasmolytic and hypotensive agents with different mechanisms of action, including accumulation of intracellular cAMP. A highly specific 122 bp domain of the K(+) channel between S5 and H5 with a 55% homology with Dros shab and mbk3 was amplified by nested PCR from chromosomal DNAS. pombe. Northern blot revealed a 1.8kb transcript. mRNA dot-blot and RNase-protected analysis revealed factors altering the K(+) channel transcription. 