Voltage-gated calcium (Ca²⁺) channels are crucial transducers that convert membrane potential changes into intracellular Ca²⁺ transients, initiating various physiological events. There are ten members of the voltage-gated Ca²⁺ channel family in mammals, each serving distinct roles in cellular signal transduction. The Caᵥ1 subfamily is involved in contraction, secretion, gene expression regulation, and synaptic transmission in neurons and specialized sensory cells. The Caᵥ2 subfamily primarily initiates synaptic transmission at fast synapses, while the Caᵥ3 subfamily is essential for repetitive firing of action potentials in cells like cardiac myocytes and thalamic neurons. Ca²⁺ channels activate on membrane depolarization and mediate Ca²⁺ influx in response to action potentials and subthreshold depolarizing signals. Ca²⁺ entering the cell serves as a second messenger, initiating contraction, secretion, synaptic transmission, enzyme regulation, and gene expression. Different types of Ca²⁺ currents are defined by their physiological and pharmacological properties, including L-type, T-type, N-type, and P/Q-type currents. The molecular structure of Ca²⁺ channels consists of α1, α2δ, β, γ, and δ subunits. The α1 subunit is the pore-forming component, while the β, α2δ, and γ subunits modulate channel properties. The three-dimensional structure of Ca²⁺ channels is not fully resolved but is known to include a pore lining formed by the S5 and S6 segments and a membrane-associated loop. Caᵥ1 channels play a key role in excitation-contraction coupling in muscle, excitation-transcription coupling in neurons, and excitation-secretion coupling in endocrine cells and specialized synapses. Caᵥ2 channels are involved in synaptic transmission, where they interact with SNARE proteins and G proteins to regulate neurotransmitter release. Caᵥ3 channels are important for rhythmic firing in repetitive firing tissues. The diversity of Ca²⁺ channel structure and function is enhanced by multiple β and α2δ subunits, which can modulate channel properties. Regulation of Caᵥ1 channels involves protein kinase A (PKA) and calmodulin, which affect channel activity and inactivation. Caᵥ2 channels are regulated by G protein pathways, which influence their voltage dependence and activation. Overall, voltage-gated Ca²⁺ channels are essential for a wide range of physiological processes, and their regulation involves complex interactions with various proteins and signaling pathways.Voltage-gated calcium (Ca²⁺) channels are crucial transducers that convert membrane potential changes into intracellular Ca²⁺ transients, initiating various physiological events. There are ten members of the voltage-gated Ca²⁺ channel family in mammals, each serving distinct roles in cellular signal transduction. The Caᵥ1 subfamily is involved in contraction, secretion, gene expression regulation, and synaptic transmission in neurons and specialized sensory cells. The Caᵥ2 subfamily primarily initiates synaptic transmission at fast synapses, while the Caᵥ3 subfamily is essential for repetitive firing of action potentials in cells like cardiac myocytes and thalamic neurons. Ca²⁺ channels activate on membrane depolarization and mediate Ca²⁺ influx in response to action potentials and subthreshold depolarizing signals. Ca²⁺ entering the cell serves as a second messenger, initiating contraction, secretion, synaptic transmission, enzyme regulation, and gene expression. Different types of Ca²⁺ currents are defined by their physiological and pharmacological properties, including L-type, T-type, N-type, and P/Q-type currents. The molecular structure of Ca²⁺ channels consists of α1, α2δ, β, γ, and δ subunits. The α1 subunit is the pore-forming component, while the β, α2δ, and γ subunits modulate channel properties. The three-dimensional structure of Ca²⁺ channels is not fully resolved but is known to include a pore lining formed by the S5 and S6 segments and a membrane-associated loop. Caᵥ1 channels play a key role in excitation-contraction coupling in muscle, excitation-transcription coupling in neurons, and excitation-secretion coupling in endocrine cells and specialized synapses. Caᵥ2 channels are involved in synaptic transmission, where they interact with SNARE proteins and G proteins to regulate neurotransmitter release. Caᵥ3 channels are important for rhythmic firing in repetitive firing tissues. The diversity of Ca²⁺ channel structure and function is enhanced by multiple β and α2δ subunits, which can modulate channel properties. Regulation of Caᵥ1 channels involves protein kinase A (PKA) and calmodulin, which affect channel activity and inactivation. Caᵥ2 channels are regulated by G protein pathways, which influence their voltage dependence and activation. Overall, voltage-gated Ca²⁺ channels are essential for a wide range of physiological processes, and their regulation involves complex interactions with various proteins and signaling pathways.