Gadolinium Inhibits Mechanoelectrical Transduction

Gadolinium (Gd3+) has been shown to prevent mechanoelectrical transduction believed to be mediated through stretch-activated channels. We investigated the possible role of Gd3+-sensitive channels in mediating baroreceptor activity in the carotid sinus of rabbits. Baroreceptor activity induced by a ramp increase of carotid sinus pressure was reduced significantly during exposure to Gd3+. The inhibition was dose-related and reversible, and was not associated with alteration of carotid sinus wall mechanics as the pressure-strain relationship was unaffected. Veratrine triggered action potentials from singleand multiple-baroreceptor fibers when their response to pressure was inhibited by Gd3+. This suggests that the effect of Gd3+ on baroreceptors in the isolated carotid sinus was specific to their mechanical activation. The results suggest that stretch-activated ion channels sensitive to Gd3+ may be the mechanoelectrical transducers of rabbit carotid sinus baroreceptors. (J. Clin. Invest. 1994. 94:2392-2396.)