Distribution and functional significance of the P-type, voltage-dependent Ca2+ channels in the mammalian central nervous system

摘要: Abstract In addition to the three types of voltage-dependent calcium channels presently recognized in CNS, L-, T- and N-types, a fourth distinct type known as P-type channel has recently been described. This channel, initially Purkinje cells (and thus name), is not blocked by dihydropyridines or ω-conotoxin (GVIA), but native funnelweb spider venom polyamine (FTX) extracted from such venom. addition, synthetic (sFTX) produced that also specifically blocks P-channels brain slices at neuromuscular junction, presynaptic Ca 2+ currents other vertebrate invertebrate forms, well expressed Xenopus oocytes following CNS mRNA injections. Using sFTX form an affinity gel, protein was isolated reconstituted into lipid bilayers where it manifests single-channel properties are electrophysiologically pharmacologically similar those P-channels. Rabbits immunized with polyclonal antibody gave positive western blot purified P-channel generated reaction product specific sites agree physiological distribution activity.