The effect of calcium channels blockers in the K+-evoked release of [3H]adenine nucleotides from rat brain cortical synaptosomes.

The role of L-,N-, P- and Q-type voltage-dependent calcium channels in K+-induced release of [3H]adenine nucleotides from rat brain cortical synaptosomes was investigated. Cd2+, a non-specific blocker of calcium channels, inhibited by 69% the release of the nucleotides induced by 33 mM K+. Nifedipine, omega-Conotoxin GVIA and omega-Agatoxin IVA had no effect whereas omega-Conotoxin MVIIC inhibited by 62% the K+ induced release of adenine nucleotides in rat brain cortical synaptosomes. It is concluded that Q-type calcium channels are directly involved in the release of adenine nucleotides in rat brain cortical synaptosomes.