DYNAMIC REGULATION OF K-EXPRESSION IN DIFFERENTIATED CELLS( CHANNEL GENE)

Recent studies have determined that K+ channel gene expression is dyna mically controlled in endocrine, cardiac, and neuronal cells. This reg ulation is induced by physiological stimuli (e.g., hormones, transmitt ers, depolarization), drugs (e.g., opiates) and with pathophysiologica l conditions (e.g,, seizures, hypertension). In many cases, alteration s in subunit expression are driven by transcriptional changes. Further more, resultant changes in excitability can be produced within hours b ecause of the rapid turnover of Kv-channel proteins. Finally, the cons equences of altering K+-channel subunit are complex because a single g ene product can participate in forming functionally distinct homomeric and heteromeric channels in the same cell. Thus, regulating K+-channe l genes constitutes a novel mechanism for producing intricate long-ter m changes in excitability. (C) 1998 John Wiley & Sons, Inc.