System and Method for Affecting Porosity of Tissue Barriers, Including Blood Brain Barrier

A medical device for delivering an active agent through a blood-brain barrier (BBB) and into a brain of a subject comprising:

• an active agent delivery system configured to deliver the active agent to the BBB;
• an electrical stimulation device including at least one electrode configured to delivery electrical stimulation to the subject to stimulate a sphenopalatine ganglion (SPG) of the subject;
• and
• a control unit in communication with the at least one electrode, the control unit including a processor and memory having processor-readable instructions, wherein when the processor-readable instructions are executed by the processor, the control unit is configured to:
• generate a first electrical stimulation signal to the at least one electrode to apply a first electrical stimulation to the subject to stimulate a sphenopalatine ganglion (SPG) of the subject thereby increasing porosity of the BBB from an initial porosity to an increased porosity, and
• generate, after said first electrical stimulation signal, a second electrical stimulation signal to the at least one electrode to apply a second electrical stimulation to the subject to stimulate the SPG of the subject thereby decreasing porosity of the BBB from the increased porosity to a decreased porosity that is less than the increased porosity.