Terazosin HCl

Terazosin HCl (CAS No.: 63074-08-8) is a synthetic small molecule with a quinazoline scaffold, classified as a highly selective α1 adrenergic receptor antagonist. It is commonly used as a benchmark compound for studying G protein-coupled receptor-mediated smooth muscle regulation, and is suitable for receptor pharmacology and pathway analysis in the context of biomedical research and drug discovery. Through competitive antagonism of the α1A, α1B, and α1D receptor subtypes, it exhibits significant selectivity over α2 receptors, thereby inhibiting norepinephrine-driven Gq/phospholipase C signaling, reducing inositol trisphosphate-mediated intracellular Ca2+ release, and attenuating downstream protein kinase C activity. Ultimately, in experimental systems, this is reflected as a phenotypic readout of reduced vascular and urogenital tract smooth muscle tone. In vitro studies show that its binding to and functional antagonism of α1 receptors are typically in the nanomolar to submicromolar range, while its activity toward α2 subtypes is significantly weaker, facilitating analysis of receptor subtype contributions and construction of selectivity profiles. In terms of applications, it is suitable for binding/displacement, calcium flux, contractility, reporter gene, and other assays in heterologous expression cells and primary smooth muscle cells. It may also be used as a pharmacological probe in preclinical animal studies to modulate endpoints such as hemodynamics and lower urinary tract function in a controlled manner (for example, for mechanistic validation and control comparisons in models such as spontaneously hypertensive rats and anesthetized dogs); in drug screening and method development, it is commonly used as a positive control or for performance calibration of experimental systems. The concentration or dose used in experiments depends on the specific experimental design, species, and readout indicators, and should be determined through preliminary experiments and methodological optimization. Major research areas include adrenergic receptor pharmacology, cardiovascular physiology, and urinary system smooth muscle biology. For laboratory research use only. Not for use in humans or veterinary applications, diagnostic procedures, or any other non-research purposes.