Navigation Links
Schizophrenia linked to dysfunction in molecular brain pathway activated by marijuana
Date:7/7/2008

PITTSBURGH, July 7 Alterations in a molecular brain pathway activated by marijuana may contribute to the cognitive symptoms of schizophrenia, according to a report in the July issue of Archives of General Psychiatry, one of the JAMA/Archives journals.

Expression of the cannabinoid 1 receptor (CB1R), the site of action of the main chemical ingredient of marijuana, is significantly reduced in the brains of individuals with schizophrenia. Activation of CB1R impairs signaling by gamma-aminobutyric acid (GABA), an important neurotransmitter essential for core cognitive processes such as working memory. The use of marijuana in individuals with schizophrenia appears to worsen this deficit in GABA synthesis.

Since reduced GABA is known to be present in schizophrenia, these findings suggest possible new drug targets that could help to improve function in people with the mental illness, University of Pittsburgh School of Medicine researchers report.

"Heavy marijuana use, particularly in adolescence, appears to be associated with an increased risk for the later development of schizophrenia, and the course of illness is worse for people with schizophrenia who use marijuana," said David A. Lewis, M.D., corresponding author of the study and UPMC Endowed Professor in Translational Neuroscience, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine. "We wanted to understand the biological mechanisms that could explain these observations, and with this study, I believe that we can narrow down at least part of the 'why' to CB1R, the receptor for both tetrahydrocannabinol (THC), the main psychoactive ingredient in marijuana, and the brains own cannabinoid chemical messengers."

Dr. Lewis and his colleagues examined specimens of brain tissue collected after death from 23 people with schizophrenia and 23 normal comparison subjects matched for a number of factors, including age and sex. The researchers evaluated levels of CB1R messenger RNA and protein, and also measured levels of glutamic acid decarboxylase (GAD-67), an enzyme that makes GABA, and cholecystokinin (CCK), a neuropeptide released from GABA neurons that, among other actions, regulates the production of the brain's own cannabinoids.

"CB1R levels were significantly 15 percent lower in the subjects with schizophrenia," Dr. Lewis said. "We measured these biochemical messengers using three techniques, and each time got the same answer less CB1R in people with schizophrenia." This reduction, he noted, appears to be the brain's way of compensating for lower levels of GABA, and the use of marijuana defeats this compensation.

"These findings may provide insight into the biological basis of why cannabis use worsens schizophrenia, and, as a result, identify a novel target for new drug development that could improve treatments available for schizophrenia," said Dr. Lewis.


'/>"/>

Contact: Michele Baum
BaumMD@upmc.edu
412-647-3555
University of Pittsburgh Schools of the Health Sciences
Source:Eurekalert

Related medicine news :

1. Violence declines with medication use in some with schizophrenia
2. Brain Activity May Predict Schizophrenia Behavior
3. Hopkins researchers discover new link to schizophrenia
4. Dr. Mei honored by mental health research charity for schizophrenia studies
5. Schizophrenia: Diagnosis Is Not Destiny - Conference
6. New Drugs No Better Than Older Ones for Schizophrenia
7. Schizophrenia Tied to Multiple Genetic Errors
8. Comparison of antipsychotic treatments in adolescents with schizophrenia
9. New genetic association with schizophrenia found by researchers
10. FDA Issues Not-Approvable Letter for Lillys Zyprexa(R) Long-Acting Injection (LAI) for Schizophrenia Treatment
11. Siblings of schizophrenia patients display subtle shape abnormalities in brain
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:12/6/2016)... ... December 06, 2016 , ... The V ... announce its Not a Moment to Lose fundraising campaign. As the V Foundation’s ... to declaring victory over cancer. The campaign aims to raise $200 million by ...
(Date:12/6/2016)... ... 2016 , ... GrekTek LLC, ( http://www.grektek.com ) an mHealth ... ) for the HealthyWatch, a new device to help patients manage their health ... while sharing these events with caregivers in real time. , “One ...
(Date:12/6/2016)... ... December 06, 2016 , ... ... the newly updated International Audit Protocol Consortium (IAPC) EHS audit protocol for ... to understand the scope of their EHS regulatory obligations and rapidly collect, share, ...
(Date:12/5/2016)... ... December 05, 2016 , ... What: Shriners Hospitals for Children, with the help ... patients – using a video monitor and web-enabled camera. Santa visits with children through ... into a Christmas Wonderland, which is where the video connection to the North Pole ...
(Date:12/5/2016)... , ... December 05, 2016 , ... ... it has been featured in SuperbCrew magazine, a leading online tech news platform ... This interview, now featured on SuperbCrew.com, explores the state of enterprise mobility security ...
Breaking Medicine News(10 mins):
(Date:12/5/2016)... Dec. 5, 2016  Sharn Anesthesia Inc. announced today ... and distribution partner for Salter Labs.  The company also ... in recognition of outstanding sales performance. Salter ... and anesthesia care, including the market gold standard ECO ... master distributor of the Parker Flex-Tip® Endotracheal Tube, which ...
(Date:12/5/2016)... , Dec. 5, 2016   BIOTRONIK today ... study. The study evaluates the safety and feasibility of ... an office setting. BioMonitor 2 is an ... that is placed underneath a patient,s skin to help ... (fainting). Atrial fibrillation is a leading cause of stroke ...
(Date:12/5/2016)... Calif. , Dec. 5, 2016 Sanovas, ... technology accelerator, announced today the launch of its wholly owned ... Logo - http://photos.prnewswire.com/prnh/20161202/445250LOGO   Logo - http://photos.prnewswire.com/prnh/20161202/445251LOGO ... ... There ...
Breaking Medicine Technology: