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:2/10/2016)... ... February 10, 2016 , ... ... offering education, research and medical media, has launched Contagion® , a ... diseases. , As the all-inclusive resource for infectious disease information, Contagion features ...
(Date:2/10/2016)... (PRWEB) , ... February 10, 2016 , ... ... company is unveiling its revolutionary new 2.0 version at the International Roofing Expo ... “put the power of the world's most advanced weather technology in the hands ...
(Date:2/10/2016)... , ... February 10, 2016 , ... ... Video Remote Interpreting (VRI) within Healthcare, recently partnered with Heart City Health ... (VRI). , For nearly 23 years, Heart City Health Center has provided the ...
(Date:2/10/2016)... Huntington, NY (PRWEB) , ... February 10, 2016 ... ... web-based compliance tracking solution, The Guard, to associations of medical professionals throughout the ... HIPAA compliance, including security risk assessments, policies and procedures, employee training, regulatory updates, ...
(Date:2/10/2016)... ... 10, 2016 , ... Emergency rooms provide emergency care to stabilize critical health ... patients with dental emergencies at risk of losing a tooth or their smiles. Dr. ... , Common dental emergencies include:, , Avulsed or knocked-out teeth ...
Breaking Medicine News(10 mins):
(Date:2/10/2016)... Calif., Feb. 10, 2016   Genomic Health, Inc. (Nasdaq: ... the quarter and year ended December 31, 2015. ... fourth quarter of 2015, compared with $69.1 million in the fourth ... currency basis, revenue increased 9 percent compared with the same period ... U.S. revenue was $63.9 million in the fourth quarter of ...
(Date:2/10/2016)... 2016 Mylan N.V. (NASDAQ, TASE: MYL) today ... ended December 31, 2015. --> ... total revenues of $9.45 billion, up 28% on a ... revenues of $9.43 billion. Excluding the impact of the ... branded generics business (the "EPD Business"), full year adjusted ...
(Date:2/10/2016)... -- CSI Specialty Group (CSI) expanded its specialty pharmacy ... Pharmacy Podcast. A free, weekly show, the Specialty Pharmacy ... discussion and context amongst specialty pharmacy peers and professionals. ... The Specialty Pharmacy Podcast, hosted by industry leader ... DiMascio, CHE, CMCE, CPC, is available for streaming and/or ...
Breaking Medicine Technology: