cGMP-specific 3',5'-cyclic phosphodiesterase 5A (PDE5A)

cGMP-specific 3',5'-cyclic phosphodiesterase 5A (PDE5A) is a key enzyme responsible for the hydrolysis of cyclic guanosine monophosphate (cGMP), a critical second messenger that mediates smooth muscle relaxation and vasodilation [1], [2]. By regulating intracellular cGMP levels, PDE5A serves as a major modulator of the nitric oxide (NO) signaling pathway, particularly in the cardiovascular and urogenital systems [4], [8]. The enzyme is predominantly expressed in the smooth muscle cells of the corpus cavernosum, pulmonary arteries, and systemic vasculature [2], [6]. In disease states, excessive PDE5A activity can lead to impaired vasodilation, contributing significantly to conditions such as erectile dysfunction (ED) and pulmonary arterial hypertension (PAH) [3], [5]. Therapeutic targeting of PDE5A involves the use of selective inhibitors like sildenafil, tadalafil, and vardenafil, which competitively bind to the enzyme's catalytic site [3], [10]. These drugs effectively increase cGMP concentrations, thereby promoting sustained vasodilation and improving blood flow in targeted tissues [4], [19]. Beyond its established roles, PDE5A is also being explored as a target for heart failure, benign prostatic hyperplasia, and certain neurodegenerative disorders due to its broader effects on inflammation and cellular signaling [2], [12], [16]. Clinical use of PDE5A inhibitors requires careful management due to potential side effects like hypotension, especially when co-administered with nitrates, and rare occurrences of visual disturbances [6], [9], [18].

Other names

PDE5PDE5ACGB-PDECN5APhosphodiesterase 5AcGMP-binding cGMP-specific phosphodiesterasecGMP-specific phosphodiesterase type 5A

Competitive inhibition of the catalytic site of PDE5A, preventing the hydrolysis of cGMP to 5'-GMP, which increases intracellular cGMP levels and enhances nitric oxide-mediated smooth muscle relaxation [3], [4], [10].