Vasodilatorische

Vasodilatorische refers to properties or effects that cause vasodilation, the widening of blood vessels. This broad concept includes agents and physiological mechanisms that increase the diameter of arteries and arterioles, thereby reducing vascular resistance and often improving tissue perfusion.

Mechanisms of vasodilation can be endothelium-dependent or endothelium-independent. Endothelium-dependent pathways involve receptors and signaling molecules produced by the vascular endothelium, notably nitric oxide (NO), which stimulates guanylate cyclase in smooth muscle to raise cGMP and promote relaxation. Prostacyclin (PGI2) and bradykinin also contribute by increasing cyclic nucleotides and triggering smooth muscle relaxation. Endothelium-independent mechanisms directly affect smooth muscle, such as hyperpolarization via potassium-channel activation, inhibition of calcium entry, or activation of cyclic nucleotide pathways independent of the endothelium.

Pharmacologically, vasodilators encompass several classes. Nitrates (eg, nitroglycerin) donate NO to cause rapid dilation, while hydralazine and minoxidil act as directly acting vasodilators. Calcium channel blockers (eg, amlodipine, diltiazem) reduce calcium entry into smooth muscle. PDE-5 inhibitors (eg, sildenafil) enhance NO signaling. ACE inhibitors and ARBs indirectly promote vasodilation by reducing angiotensin II–related vasoconstriction. Endothelin receptor antagonists are used in conditions like pulmonary arterial hypertension. Some agents target specific vascular beds, with varying effects on systemic versus pulmonary circulation.

Clinical use and considerations: vasodilators are used to treat hypertension, angina, heart failure, and pulmonary arterial hypertension, among others. They can lower blood pressure and afterload but may cause hypotension, headache, edema, or reflex tachycardia; drug interactions, such as nitrate–PDE-5 inhibitor combinations, require caution. The term vasodilatorische is commonly used in German pharmacology to describe such effects.