Exocytotic Ca2+ channels in mammalian central neurons

Cytochrome P450 CYP2J9, a New Mouse Arachidonic Acid ω-1 Hydroxylase Predominantly Expressed in Brain

“…In this report, we describe the cDNA cloning of CYP2J9, a new mouse P450 that is primarily expressed in the brain, regulated during postnatal brain development and active in the biosynthesis of 19-HETE. We further demonstrate that CYP2J9 is particularly abundant in cerebellar Purkinje cells and that 19-HETE inhibits P/Qtype Ca 2ϩ channels, voltage-gated channels that are known to be expressed preferentially in Purkinje cells and are involved in triggering the release of neurotransmitters (59,60).…”

“…An important finding of this study is that the major CYP2J9 product (19-HETE) significantly inhibits voltage-gated Ca 2ϩ channels. It is now well established that Ca 2ϩ influx through voltage-gated channels is important in triggering release of neurotransmitters, stimulating contraction of smooth and cardiac muscle, initiating the transcription of numerous genes, and controlling other critical cellular processes (60). In the central nervous system, Ca 2ϩ influx through L-type Ca 2ϩ channels may initiate specific gene expression, whereas Ca 2ϩ influx through P/Q-and N-type Ca 2ϩ channels is more important for triggering neurotransmitter release (60).…”

Constitutive activity of the Ghrelin receptor reduces surface expression of voltage-gated Ca2+ channels in a CaVβ-dependent manner

“…Depending on cell type, developmental stage and subcellular location, different Ca V subtypes are involved in orchestrating Ca 2+ -dependent signaling; Ca V 1 and Ca V 2 channels trigger transcription-dependent forms of synaptic plasticity (Ca V 1.2 and Ca V 1.3) (Wheeler et al, 2008) and fast neurotransmitter release (Ca V 2.1-3) (Dunlap et al, 1995;Catterall and Few, 2008;Pan and Zucker, 2009), whereas, Ca V 3 and Ca V 1.3 channels, that activate closer to the resting membrane potential, are involved in regulating cell excitability and shaping neuronal firing patterns Perez-Reyes, 2003;McKay et al, 2006;Xu and Lipscombe, 2001).…”

Voltage-gated Ion Channels

“…Surprisingly, selective pressure from the presence of STX in the natural environment or TTX Heineman et al, 1992 Fig ), some of the Moczydlowski et al, 1986Ohizumi et al, 1986Yanagawa et al, 1986 mutations that affect TTX affinity do not alter -conotoxin binding, suggesting that these two toxins share an overlapping but not identical μ receptor site ( ; ; , ). Moreover, recent studies of a toxin from the South Dudley et al, 1995Stefan et al, 1994Chahine et al, 1995 American spider showed that it blocks sodium currents in a state-dependent manner and competes for binding with Phoneutria nigriventer μ instrumental in identifying the pore loop and in clarifying the regions of the channel structure involved in the ion selectivity filter, and one can anticipate that mapping the sites of interaction of toxin will provide further insight into these overlapping toxin binding P. nigriventer sites and their relationship to the ion selectivity filter.…”

“…The Ca 2 subfamily of calcium channels (Ca V V 2.1 to Ca 2.3) conduct N-, P/Q-and R-type calcium currents that initiate fast synaptic transmission at synapses in the central and V peripheral nervous systems and are blocked specifically by peptide neurotoxins from spider and cone snail venoms (Snutch and Reiner, ; ; ; ). The Ca 3 subfamily of calcium channels (Ca 3.1 to Ca 3.3) conduct 1992 Dunlap et al, 1995Catterall, 2000bOlivera et al, 1994 V V V T-type calcium currents that are important for repetitive action potential firing of neurons in the brain and in the pacemaker cells of the sino-atrial node in the heart ( ). The protein-protein interactions as well as the functional and regulatory properties of Perez-Reyes, 2003 different subfamilies of these ion channels are adapted to their distinct roles in electrical signaling and cellular signal transduction.…”