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Research area: Voltage-gated Na channels are responsible for initiation of electrical signaling in nerve, muscle and other excitable cells, and voltage-gated Ca channels are responsible for initiation of synaptic transmission in neurons, excitation-contraction in muscle, secretion in endocrine cells, and many other processes.
Ca++ palys important role in trigger presynaptic transmitter release
Ca2.1, (P/Q type Ca channel) CaS ( Ca sensor)dependent faciliation IQ-like motif(IM) CaM-binding domain (CBD) CaS dependent inactivation
Methods • Cultured SCG(superior cervical ganglion )neuron form fast cholinergic synaptic transmission between them cDNAstransfection to exogenous express WT or Mutant P/Q type Calcium channels in SCG • Whole cell recording • Sharp electrode intracellular reocording
Calcium Dependent Facilitation and Inactivation of CaV2.1 Channels EPSP = k*(ICa)n k = 1 ,n = 3.5
Plasticity of Synaptic Transmission Mediated by CaV2.1 Channels during Bursts of Neuronal Activity
Summary • A mutation of the Iq-like motif in the C terminus that blocks Ca2+/CaS dependent facilitation of the P/Q-type Ca2+ current markedly reduces facilitation of synaptic transmission. • Deletion of the nearby calmodulin-binding domain,which inhibits CaS-dependent inactivation,substantially reduces depression of synaptic transmission. • Residual Ca2+ in presynaptic terminals can act through CaS dependent regulation of CaV2.1 channels to induce short-term synaptic facilitation and rapid synaptic depression. Activity-dependent regulation of presynaptic CaV2.1 channels by CaS proteins may therefore be a primary determinant of short-term synaptic plasticity and information-processing