William Atkins
Wednesday, 18 February 2009 19:54
Science -
Biology
Page 2 of 4
They state,
“Recent trends in the high usage of methylphenidate for both therapeutic and nontherapeutic purposes prompted us to investigate the long-term effects of exposure to the drug on neuronal adaptation.” [Abstract]
The researchers—led by Dr. Yong Kim, a senior research associate at Rockefeller University—compared MPH and cocaine over a fourteen-day period. They injected laboratory mice daily doses in the amount of 15 milligrams per kilogram.
They then searched for changes in dendritic spine formation, which is associated with the development of synapses and communications among nerve cells.
The researchers were also interested in looking for delta Fos B within the brain, which is involved in the response in the brain to the introduction of illicit drugs that are addictive.
They found that a larger number of “medium-sized” spiny neurons formed in the core and shell of nucleus accumbens (NAcc) from ventral and dorsal striatum. The use of cocaine caused these MSN to form in all types of striatum.
NAcc is a group of neurons in the forebrain that are thought be involved in such sensations as pleasure, laughter, reward, and fear, along with risks from addiction.
Overall, the researchers found that the number of “shorter-sized” spiny neurons increased less for methylphenidate (MPH) than for cocaine, while the number of “longer-sized” spiny neurons increased more for MPH than for cocaine.
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