Researchers in Germany have created an implantable device that reduces blood pressure by sending electrical signals to the brain.

The device has successfully reduced the blood pressure in rats by 40 percent without any major side effects, and could offer hope for a significant proportion of patients worldwide who do not respond to existing medical treatment for the condition.

The device consists of 24 individual electrodes that are integrated into a micro-machined cuff. It is designed to wrap around the vagal nerve, which extends from the brainstem to the thorax and abdomen, supplying and stimulating various major organs including the heart and major blood vessels.

The device works by picking up signals from specific sensors, known as baroreceptors, which are activated when blood vessels stretch. Some baroreceptors are grouped together in concentrated areas in the aortic arch and report their information to the brainstem via fibres in the vagal nerve. These baroreceptors function to control short-term fluctuations in blood pressure.

The device has been designed to identify only those fibres that influence the blood pressure and avoid those that are responsible for heart rate, the power of heart beat, ventilation and other vital functions.

The results have been published in IOP Publishing's Journal of Neural Engineering.