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

The role of L-,N-, P- and Q-type voltage-dependent calcium channels in K+-i nduced release of [H-3]adenine nucleotides from rat brain cortical synaptos omes was investigated. Cd2+, a non-specific blocker of calcium channels, in hibited by 69% the release of the nucleotides induced by 33 mM K+. Nifedipi ne, omega-Gonotoxin GVIA and omega-Agatoxin IVA had no effect whereas omega -Conotoxin MVIIC inhibited by 62% the K+ induced release of adenine nucleot ides in Pat brain cortical synaptosomes. It is concluded that Q-type calciu m channels are directly involved in the release of adenine nucleotides in r at brain cortical synaptosomes. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.