Researchers at Boston University School of Medicine (BUSM) and McLean Hospital have found that practicing yoga may elevate brain gamma-aminobutyric (GABA) levels, the brain's primary inhibitory neurotransmitter. The findings, which appear in the May issue of the Journal of Alternative and Complementary Medicine, suggest that the practice of yoga be explored as a possible treatment for anxiety and depression, disorders associated with low GABA levels.
The World Health Organization reports that mental illness makes up to fifteen percent of disease in the world. Anxiety and depression disorders both contribute to this burden and are associated with GABA receptor levels. Currently, these disorders have been successfully treated with pharmaceutical agents designed to increase GABA effectiveness.
Using magnetic resonance spectroscopic imaging, the researchers compared the GABA levels of eight subjects prior to and after one hour of yoga, with 11 subjects who did no yoga but instead read for one hour. The researchers found a twenty-seven percent increase in GABA levels in the yoga practitioner group after their session, but no change in the comparison subject group after their reading session. The acquisition of the GABA levels was done using a magnetic resonance spectroscopy technique developed by J. Eric Jensen, PhD, an assistant professor of psychiatry at Harvard Medical School and an associate physicist at McLean Hospital.
According to the researchers, yoga has shown promise in improving symptoms associated with anxiety, depression and epilepsy. "Our findings clearly demonstrate that in experienced yoga practitioners, brain GABA levels increase after a session of yoga," said lead author Chris Streeter, MD, an assistant professor of psychiatry and neurology at BUSM and a research associate at McLean Hospital.
"This study contributes to the understanding of how the GABA system is affected by both pharmacologic and behavioral interventions and will help to guide the development of new treatments for low GABA states," said co-author Domenic Ciraulo, MD, professor and chairman of the department of psychiatry at BUSM.
"The development of an inexpensive, widely available intervention such as yoga that has no side effects but is effective in alleviating the symptoms of disorders associated with low GABA levels has clear public health advantage," added senior author Perry Renshaw, MD, PhD, director of the Brain Imaging Center at Harvard-affiliated McLean Hospital.
This study was supported in part by grants from the national Institute of Drug Abuse; the National Institute on Alcohol Abuse and Alcoholism; the National Center for Research Resources, and the Gennaro Acampora Charity Trust to the Division of Psychiatry, Boston Medical Center.
Streeter CC, Jensen JE, Perlmutter RM, Cabral HJ, et al.
Yoga Asana Sessions Increase Brain GABA Levels: A Pilot Study
J Altern Complement Med. 2007 May;13(4):419-42 [Abstract]
The neurotransmitter/amino acid GABA is produced as a byproduct of the KREB cycle that fuels the brain. Despite often repeated claims, anxiety (and depression) is not caused by insufficient GABA. Nor do commonly used GABAergic drugs such as the benzodiazepinesincrease the amount of GABA in the brain.
However, there is evidence(1) that GABA binding to GABA(A) receptors is reduced in anxiety, and to a lesser extent, depression, mostly due to an impairment(2) of benzodiazepine binding at the GABA(A) receptors. Benzodiazepines increase the affinity of GABA binding sites for GABA so that more receptors are activated by the neurotransmitter.
(1)
Kosel M, Rudolph U, Wielepp P, et al. (2004) Diminished GABA(A) receptor-binding capacity and a DNA base substitution in a patient with treatment-resistant depression and anxiety. Neuropsychopharmacology; vol 29(2):347-50. Abstract
(2)
Bremner JD, Innis RB, Southwick SM, et al. (2000) Decreased benzodiazepine receptor binding in prefrontal cortex in combat-related posttraumatic stress disorder. Am J Psychiatry Jul; vol 157(7):1120-6 Abstract
Johnson MR, Marazziti D, Brawman-Mintzer O, et al (1998) Abnormal peripheral benzodiazepine receptor density associated with generalized social phobia. Biol Psychiatry Feb 15; vol 43(4):306-9 Abstract
Morimoto K. (1999) Benzodiazepine receptor imaging in the brain: recent developments and clinical validity. Kaku Igaku May; vol 36(4):307-13 Ab stract
Tiihonen J, Kuikka J, Rasanen P, et al. (1997) Cerebral benzodiazepine receptor binding and distribution in generalized anxiety disorder: a fractal analysis. Mol Psychiatry Oct-Nov; vol 2(6):463-71 Abstract
Tokunaga M, Ida I, Higuchi T, Mikuni M. (1997) Alterations of benzodiazepine receptor binding potential in anxiety and somatoform disorders measured by 123I-iomazenil SPECT. Radiat Med May-Jun; vol 15(3):163-9 Abstract