Stimulating the human midbrain to reveal the link between pain and blood pressure

• Published in: Pain (Amsterdam) Vol. 124; no. 3; pp. 349 - 359
• Main Authors: Green, Alexander L., Wang, Shouyan, Owen, Sarah L.F., Xie, Kangning, Bittar, Richard G., Stein, John F., Paterson, David J., Aziz, Tipu Z.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2006; Elsevier
• Subjects: Adult; Aged; Analgesia - methods; Biological and medical sciences; Blood pressure; Blood Pressure - physiology; Chronic Disease; Deep Brain Stimulation; Electrodes; Female; Fundamental and applied biological sciences. Psychology; Humans; Linear Models; Male; McGill Pain Questionnaire; Middle Aged; PAG; Pain; Pain - physiopathology; Pain Management; Pain Measurement; Periaqueductal Gray - physiology; Periaqueductal grey; Peripheral nervous system. Autonomic nervous system. Neuromuscular transmission. Ganglionic transmission. Electric organ; Prospective Studies; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Sympathetic Nervous System - physiology; Vertebrates: nervous system and sense organs; Visual analogue score; Pain; Deep brain stimulation; PAG; Blood pressure; McGill Pain Questionnaire; Visual analogue score; Periaqueductal grey; Human; Electrical stimulus; Central nervous system; Midbrain; Sympathetic nervous system; Arterial blood; Analgesia; Autonomic nervous system; Modulation; Pain Questionnaire McGill; Arterial pressure; Hemodynamics
• ISSN: 0304-3959; 1872-6623
• DOI: 10.1016/j.pain.2006.05.005

The periaqueductal grey area (PAG) in the midbrain is an important area for both cardiovascular control and modulation of pain. However, the precise relationship between pain and blood pressure is unknown. We prospectively studied 16 patients undergoing deep brain stimulation of the rostral PAG for chronic pain. Pre-operatively, post-operatively, and at 1 year, pain scores were assessed using both visual analogue scores and the McGill Pain Questionnaire. Patients were tested post-operatively to determine whether electrical stimulation of the PAG would modulate blood pressure. We found that the degree of analgesia induced by deep brain stimulation of the rostral PAG in man is related to the magnitude of reduction in arterial blood pressure. We found that this relationship is linear and is related to reduced activity of the sympathetic nervous system. Thus stimulation of the PAG may partly control pain by reducing sympathetic activity as predicted by William James over a century ago.