Article: Relaxant effects of mefloquine on vascular smooth muscle in vitro

We have studied the effects of mefloquine on isolated rat aorta. Mefloquine (10(-8) to 1.6 x 10(-4) mol.l-1) relaxed aortic rings precontracted with both noradrenaline (10(-7) mol.l-1) and potassium chloride (60 mmol.l-1). The mefloquine-induced relaxation was somewhat attenuated by removal of the endothelium. Contractile responses to noradrenaline, potassium chloride, and calcium chloride were reduced by incubating the aortic rings in physiological salt solution containing mefloquine, suggesting that mefloquine reduces calcium influx, which is required for excitation-contraction coupling. The results show that mefloquine relaxes vascular smooth muscle via mechanisms which are partly endothelium-dependent and which is also associated with inhibition of Ca2+ influx from the extracellular medium.

Citing Articles

Hydroxychloroquine induces endothelium-dependent and endothelium-independent relaxation of rat aorta.

Arslan S, Dogan M, Cam S, Omar I, Uysal F, Parlar A Turk J Med Sci. 2022; 52(3):848-857.

PMID: 36326331 PMC: 10390209. DOI: 10.55730/1300-0144.5382.

References

1.

Meisheri K, Hwang O, van Breemen C . Evidence for two separated Ca2+ pathways in smooth muscle plasmalemma. J Membr Biol. 1981; 59(1):19-25. DOI: 10.1007/BF01870817. View

2.

Turlapaty P, Altura B, Altura B . Influence of tris on contracile responses of isolated rat aorta and portal vein. Am J Physiol. 1978; 235(2):H208-13. DOI: 10.1152/ajpheart.1978.235.2.H208. View

3.

Ebeigbe A, Aloamaka C . Mechanism of hydralazine-induced relaxation of arterial smooth muscle. Cardiovasc Res. 1985; 19(7):400-5. DOI: 10.1093/cvr/19.7.400. View

4.

BOHR D . Vascular Smooth Muscle: Dual Effect of Calcium. Science. 1963; 139(3555):597-9. DOI: 10.1126/science.139.3555.597. View

5.

Webster H, Boudreau E, Pavanand K, Yongvanitchit K, Pang L . Antimalarial drug susceptibility testing of Plasmodium falciparum in Thailand using a microdilution radioisotope method. Am J Trop Med Hyg. 1985; 34(2):228-35. DOI: 10.4269/ajtmh.1985.34.228. View

6.

Bolton T . Mechanisms of action of transmitters and other substances on smooth muscle. Physiol Rev. 1979; 59(3):606-718. DOI: 10.1152/physrev.1979.59.3.606. View

7.

FURCHGOTT R, Zawadzki J . The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature. 1980; 288(5789):373-6. DOI: 10.1038/288373a0. View

8.

BOHR D . Vascular smooth muscle updated. Circ Res. 1973; 32(6):665-72. DOI: 10.1161/01.res.32.6.665. View

9.

Mecca T, Webb R . Vascular responses to serotonin in steroid hypertensive rats. Hypertension. 1984; 6(6 Pt 1):887-92. DOI: 10.1161/01.hyp.6.6.887. View

10.

Schwartz D, Weber W, Richard-Lenoble D, Gentilini M . Kinetic studies of mefloquine and of one of its metabolites, Ro 21-5104, in the dog and in man. Acta Trop. 1980; 37(3):238-42. View

11.

Webb R, BOHR D . Mechanism of membrane stabilization by calcium in vascular smooth muscle. Am J Physiol. 1978; 235(5):C227-32. DOI: 10.1152/ajpcell.1978.235.5.C227. View

12.

Ebeigbe A, Aloamaka C, Alohan F . Mechanism of chloroquine-induced inhibition of smooth muscle contraction. Arch Int Pharmacodyn Ther. 1986; 280(2):254-63. View

13.

Altura B, Altura B . Barbiturates and aortic and venous smooth-muscle function. Anesthesiology. 1975; 43(4):432-44. DOI: 10.1097/00000542-197510000-00009. View

Relaxant Effects of Mefloquine on Vascular Smooth Muscle in Vitro