Navigation Links
New clue to cocaine addicts' quirky behavior

Researchers working with rats have zeroed in on the brain circuitry mechanism whose disruption contributes to the impulsive behavior seen in users of cocaine as well as other psychostimulant drugs. The same circuitry has been implicated in such disorders as schizophrenia, depression, and post-traumatic stress disorder, wrote the researchers.

Yukiori Goto and Anthony A. Grace of the University of Pittsburgh described their findings in the July 21, 2005, issue of Neuron. In their studies, they sought to understand the effects of cocaine sensitization on the connections between two higher brain regions--the prefrontal cortex and the hippocampus--and the nucleus accumbens, which is the region in the limbic system involved in processing reward behavior. The prefrontal cortex is involved in processing information, and the hippocampus is involved in learning and memory.

The connections to the nucleus accumbens seem to be bidirectional, said the researchers, and the interactions with the prefrontal cortex and hippocampus could affect the "plasticity" of connections in the neurons of the nucleus accumbens. This means that disruptions to the normal connections could affect behavior.

The researchers' electrophysiological studies of the effects of cocaine on this circuitry demonstrated that the drug did disrupt this normal plasticity. They found that the cocaine induced abnormal enhancement of neuronal connections--a phenomenon called long-term potentiation (LTP).

The researchers also performed behavioral studies on the cocaine-sensitized rats, to explore the behavioral effects of this disruption. In these studies, they placed the rats in a plus-shaped maze. The rats were taught that in response to a visual cue they should turn left or right toward one arm or the other of the maze to obtain a piece of cereal.

Goto and Grace found that, while the cocaine-sensitized rats learned the correct response strategy faster than normal rats, they wer e significantly less able to change strategies when they were required to ignore the cue and always make a left or right turn to receive the reward.

"Thus, although abnormally induced LTP by psychostimulants at limbic inputs might not interfere with learning a response strategy, it may reduce the capacity of these animals to consider alternate response strategies," concluded Goto and Grace. "In this way, the disruption of synaptic plasticity by cocaine sensitization may contribute to the affective- and context-inappropriate impulsive behaviors that are characteristic of drug addiction."

This work was supported by USPHS and National Alliance for Research on Schizophrenia and Depression Young Investigator Award. Y.G. is NARSAD Essel Investigator.

Goto and Grace: "Dopamine-dependent Interactions between Limbic and Prefrontal Cortical Plasticity in the Nucleus Accumbens: Disruption by Cocaine Sensitization" Publishing in Neuron, Vol. 47, July 21, 2005, pages 255?66. DOI 10.1016/j.neuron.2005.06.017. www.neuron.org


'"/>

Source:Cell Press


Related biology news :

1. Portable cocaine sensor developed at UC Santa Barbara
2. High resolution snapshots detail dynamics of a cocaine antibody
3. Genetically altered mice no longer like cocaine
4. High-tech research shows cocaine changes proteins and brain function
5. Altered perception of reward in human cocaine addiction
6. Scientists design simple dipstick test for cocaine, other drugs
7. Prenatal cocaines lasting cellular effects
8. Rensselaer researchers develop approach that predicts protein separation behavior
9. Scientists uncover new clues about brain function in human behavior
10. Single gene is genetic switch for fly sexual behavior
11. Using the genomic shortcut to predict bacterial behavior
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:1/20/2016)... Jan. 20, 2016   MedNet Solutions , an ... spectrum of clinical research, is pleased to announce the ... achievements are the result of the company,s laser focus ... eClinical , it,s comprehensive, easy-to-use and highly affordable ... --> Key MedNet growth achievements in 2015 include: ...
(Date:1/13/2016)... January 13, 2016 --> ... a new market report titled - Biometric Sensors Market - ... 2015 - 2023. According to the report, the global biometric sensors ... anticipated to reach US$1,625.8 mn by 2023, expanding at ... terms of volume, the biometric sensors market is expected ...
(Date:1/8/2016)... ANGELES and MANCHESTER, United Kingdom ... ("BBI"), a developer of innovative sensor-based diagnostic products, today announced ... financed by new and existing investors.  Proceeds from the financing ... SEM Scanner , a hand-held device for detecting early-stage pressure ... Ireland after receiving CE Mark approval. ...
Breaking Biology News(10 mins):
(Date:2/8/2016)... 8, 2016 --> ... an innovation-driven oncology company developing next generation cancer ... today announced that chairman emeritus of Tata Sons ... the company as part of the first close ... investors Navam Capital and Aarin Capital. ...
(Date:2/8/2016)... 2016  BioElectronics Corporation (OTC Pink: BIEL), the ... that it is responding to a notice of ... and Exchange Commission posted on the agency website.  ... the Board of BioElectronics Corporation and the Edward ... The Fuqua School of Business, Duke University.   ...
(Date:2/8/2016)... ... 2016 , ... Franz Inc. , an early innovator ... announced the availability of AllegroGraph 6, the leading Semantic Graph Database with certification ... Program (CCPT). AllegroGraph is the first Semantic Graph Database to be certified ...
(Date:2/8/2016)... Mich. , Feb. 8, 2016  Diplomat Pharmacy, Inc. (NYSE: DPLO) announced today that its ... a specialty pharmacy resource–user-centric, story-driven, knowledge-based and mobile-friendly. ... ... ... "The goal ...
Breaking Biology Technology: