Effects of sodium selenite on vascular smooth muscle reactivity.
The effects of sodium selenite (Na(2)SeO(3)) on the vascular smooth muscle reactivity of rabbit aorta were studied. In isolated rabbit aorta, Na(2)SeO(3) inhibited contractile response to phenylephrine and developed a lasting contracture in the vascular tissue. Relaxation in phenylephrine-precontracted aortic rings induced by sodium nitroprusside and 8-bromo-guanosine 3':5'-cyclic-monophosphate was also inhibited. Preliminary data obtained with ascorbic acid suggested a partial involvement of an oxidative mechanism. Excluding the possibility that Se damages actin or modifies its distribution (immunohistochemical evaluation), results indicate that Se alters vascular smooth muscle reactivity by inhibiting both its contracting and relaxing properties. Calcium-dependent mechanisms appear to be primarily involved and an interference with calcium re-uptake by sarcoplasmic reticulum as a possible site of Se vascular action could be hypothesized.
Togna
G
G
Institute of Medical Pharmacology, University of Rome 'La Sapienza', P.le A. Moro, Rome, 5-00185, Italy.
Russo
P
P
Pierconti
F
F
Caprino
L
L
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D010656:Phenylephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D018038:Sodium Selenite / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D014665:Vasodilator Agents; D009599:Nitroprusside; D010656:Phenylephrine; C016276:8-bromocyclic GMP; D006152:Cyclic GMP; D018038:Sodium Selenite