Intracellular calcium signaling pathway in vascular smooth muscle

The **intracellular calcium signaling pathway in vascular smooth muscle** governs fundamental processes involved in regulating vascular tone, contractility, and blood pressure[1][2][5][6]. In vascular smooth muscle cells (VSMCs), an increase in intracellular Ca²⁺ concentration is typically mediated by: - **Calcium influx** through plasma membrane ion channels, especially L-type voltage-dependent calcium channels (VDCCs), as well as T-type and various transient receptor potential (TRP) channels[1][2][5][6]. - **Release of Ca²⁺** from intracellular stores, such as the sarcoplasmic reticulum, via ryanodine receptors (RyR) and inositol 1,4,5-trisphosphate receptors (IP₃R)[1][2][4][5][6]. Activation of this pathway often begins with G-protein-coupled receptors (GPCRs) responding to physiological stimuli, which leads to the production of secondary messengers (e.g., IP₃), triggering intracellular Ca²⁺ release from stores or promoting Ca²⁺ entry from the extracellular space[3][5]. Elevated Ca²⁺ binds to calmodulin, activating myosin light chain kinase (MLCK), which phosphorylates myosin, enabling actin-myosin interaction and smooth muscle contraction[5][6]. This pathway also affects elastic and adhesive functions of VSMCs by modulating cytoskeletal proteins and integrin-mediated interactions with the extracellular matrix[2]. Relaxation is mediated by mechanisms that decrease cytosolic Ca²⁺, including SERCA pumps, mitochondrial Ca²⁺ uniporters, sodium-calcium exchangers, and plasma membrane Ca²⁺-ATPases[5]. **Note:** This entry is not a single molecule, protein, or classical target such as a "receptor," "enzyme," or "ion channel," but rather a broad cellular pathway involving multiple molecular components (e.g., channels, receptors, kinases)[1][4][5]. Therefore, it should not be considered a single therapeutic target, but many core proteins within this pathway (such as L-type calcium channels, ryanodine receptors) are individually considered drug targets.

Other names

Calcium signaling in vascular smooth muscleVSMC calcium signaling

Calcium channel blockade (reduces calcium influx through voltage-gated channels) - Modulation of intracellular calcium release (inhibition or activation of ryanodine or IP₃ receptors) - Inhibition of contractile apparatus activation