Which Substance Causes Blood Vessel Constriction?

Among the options given:

1. Carbon monoxide:
   At low concentrations, carbon monoxide can have vasodilatory effects by activating soluble guanylate cyclase, though it is not primarily recognized as a vasoconstrictor.

2. Nitric oxide (NO):
   A well-known vasodilator, NO is produced by endothelial cells to relax vascular smooth muscle and reduce blood pressure.

3. Endothelin-1 (ET-1):
   Synthesized by endothelial cells, endothelin-1 is acknowledged as the most potent endogenous vasoconstrictor. It acts primarily via ETAA receptors on vascular smooth muscle causing strong and sustained vasoconstriction, significantly affecting vascular tone and blood pressure.pmc.ncbi.nlm.nih+3

4. Atrial natriuretic peptide (ANP):
   A cardiac hormone that induces vasodilation, promoting blood vessel relaxation and encouraging sodium and water excretion for reducing blood volume and pressure.

Mechanism of Endothelin-1 Mediated Vasoconstriction

• ET-1 binds to ETAA receptor on vascular smooth muscle cells.

• Activates G protein coupled receptor pathways.

• Increases intracellular calcium.

• Leads to smooth muscle contraction and vasoconstriction.

• Plays roles in maintaining basal vascular tone and pathological states like hypertension.

Summary Table

Conclusion

The substance that causes constriction of blood vessels is:

(3) Endothelin-1

Additional Insights

Endothelin-1’s potent vasoconstrictive properties make it a central player in regulating vascular resistance and blood pressure, as well as a target for therapeutic interventions in cardiovascular diseases.

Would a discussion on therapeutic targeting of endothelin receptors in hypertension and pulmonary arterial hypertension be the next useful topic?

(3) Endothelin – 1 causes constriction of blood vessels. It is a potent endogenous vasoconstrictor peptide released by endothelial cells, acting on vascular smooth muscle to increase intracellular calcium and induce contraction. In contrast, carbon monoxide, nitric oxide, and atrial natriuretic peptide primarily produce vasodilation