MODULATION OF VOLTAGE-DEPENDENT CALCIUM CHANNELS BY G-PROTEINS

Voltage-gated calcium channels are found in all excitable cells, in wh ich they regulate many important physiological functions, including ex citability, gene transcription, muscle contraction, and neurotransmitt er and hormone release. The differential modulation of calcium channel s by intracellular second messengers constitutes a key mechanism for c ontrolling calcium influx. Recent advances have provided important clu es to the underlying molecular mechanisms involved in the inhibition o f N-type and P/Q-type calcium channels by a membrane-delimited G-prote in-dependent pathway.