Hypertension induced by electrical stimulation of the subfornical organ (SFO)

In urethane anaesthetized rats, electrical, low intensity stimulations using bipolar concentric electrodes or monopolar glass pipettes were applied to SFO and to surrounding structure's populations. Blood pressure, recorded from the femoral artery, was systematically and rapidly increased when the electrical, as well as the mechanical (electrode displacements) stimulations were located within the SFO populations. Remote from the SFO, stimulations either were ineffective or produced non reliable responses. SFO cells seen to be involved in the defense against all hydroionic deficiencies, including those of blood pressure.