Diosmin-induced increase in sensitivity to Ca2+ of the smooth muscle contractile apparatus in the rat isolated femoral vein.
The effect of diosmin, a flavone derivative, on the Ca2+ sensitivity of the venous contractile apparatus was investigated in chemically (beta-escin) skinned strips from the rat isolated femoral vein. Diosmin (0.5-10 microM) shifted to the left the concentration-response curve to Ca2+ (0.05-5 microM). The maximal effect was observed in the presence of 1 microM diosmin which increased the contractile response evoked by 0.15 microM Ca2+ from 26.3% to 78.9% of the maximal Ca(2+)-induced response. This work demonstrates that the venotonic action of diosmin involves an increase in the Ca2+ sensitivity of the contractile apparatus. Such a mechanism of action could represent a new and important means of therapeutic control of vasomotor activity.
Laboratoire de Physiologie, Université de Bordeaux II, France.
J P
JP
Savineau
R
R
Marthan
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004145:Diosmin / Q000494:pharmacology*; D004928:Escin / Q000494:pharmacology; D005268:Femoral Vein / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D014661:Vasoconstriction / Q000187:drug effects*
D004928:Escin; D004145:Diosmin; D002118:Calcium