Hydralazine lowers blood pressure through which primary sub-mechanism at the vascular smooth muscle level?

• A Inhibition of L-type voltage-gated calcium channels
• B Stimulation of endothelial nitric oxide synthase via an H2S-dependent pathway
• C Blockade of inositol 1,4,5-trisphosphate receptors on sarcoplasmic reticulum
• D Opening of ATP-sensitive potassium channels (KATP), causing hyperpolarisation ✓

Explanation

Hydralazine relaxes arteriolar smooth muscle primarily by opening KATP channels, which hyperpolarises the cell membrane, reducing calcium influx and promoting vasodilation. Additionally, hydralazine may act as a hydrogen sulfide donor, contributing to its vasodilatory effect. It preferentially dilates arterioles over veins (reducing afterload), sparing preload, unlike nitrates.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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