GADOLINIUM INHIBITS MECHANOELECTRICAL TRANSDUCTION IN RABBIT CAROTID BARORECEPTORS - IMPLICATION OF STRETCH-ACTIVATED CHANNELS

Gadolinium (Gd3+) has been shown to prevent mechanoelectrical transduc tion believed to be mediated through stretch-activated channels. We in vestigated the possible role of Gd3+-sensitive channels in mediating b aroreceptor activity in the carotid sinus of rabbits. Baroreceptor act ivity induced by a ramp increase of carotid sinus pressure was reduced significantly during exposure to Gd3+. The inhibition was dose-relate d and reversible, and was not associated with alteration of carotid si nus wall mechanics as the pressure-strain relationship was unaffected. Veratrine triggered action potentials from single- and multiple-baror eceptor 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 result s suggest that stretch-activated ion channels sensitive to Gd3+ may be the mechanoelectrical transducers of rabbit carotid sinus barorecepto rs.