Implantable stimulating electrode for baroreceptor afferent nerves in rabbits.

An implantable stimulating electrode was developed for baroreceptor afferent nerves in the freely moving rabbit (nerve diam 0.1-0.2 mm). It consists of highly flexible electrode leads (coiled Pt-Ir wire) and silicone rubber (Silastic) as insulation. The electrodes were shown to be effective for up to 245 days after implantation in the neck. Electrode failure was due to dislodgment of the electrode (early failures) or (ultimately) cable breakage. Heart rate and blood pressure responses of separate and combined stimulation of depressor and carotid sinus nerves are shown. In vitro studies demonstrated some current leakage from the electrode to surrounding tissues, but the in vivo measurements show the validity of the method.