Rimobant (Acomplia) May Affect Brain Development in Kids
Weight loss drugs are big pharmaceutical business these days–The new anti-obesity drug Rimobant is a different class of medications than previous weight loss drugs. It blocks receptors in the brain that are similar to those that marijuana activates when it causes “the munchies”. New research suggests caution should be used when the drug is given to patients whose brain is not fully matured (teenagers and children) because of concern that it may alter the developmental process.
Prescription drugs for weight loss that achive their effects by blocking brain transmitter chemicals similar to those in marijuana could also alter the brain development in young children, according to a new study from MIT’s Picower Institute for Learning and Memory.
Marijuana is known to be a powerful appetite inducing drug, and a new class of weight loss drugs—such as rimonabant (trade name Acomplia) from Sanofi-Aventis and awaiting approval for use in the United States—achieve their effects by preventing brain receptors that bind to marijuana and other cannabinoids from becoming activated.
Marijuana, (scientific name Cannabis sativa), has compounds that are termed cannabinoids. But other cannabinoids (endocannabinoids are the brain chemicals generated naturally inside the body).
The MIT study, was performed on mice, showed that blocking cannabinoid receptors could also suppress the adaptive rewiring of the brain necessary for brain development in children. The work is reported in the May 8 issue of Neuron.
“Our finding of a profound disruption of cortical plasticity in juvenile mice suggests caution is advised in the use of such compounds in children,” wrote lead author Mark F. Bear, director of the Picower Institute and Picower Professor of Neuroscience.
The researchers investigated plasticity—the brain’s ability to change in response to experience—by temporarily depriving newborn mice of vision in one eye soon after birth. This well-known experiment induces a long-lasting loss of synapses that causes blindness in the covered eye, while synapses shift to the uncovered eye. How and where this synaptic shift occurs in the primary visual cortex has remained controversial.
Understanding the mechanism behind this phenomenon is key because the same brain mechanisms are used for normal development and may go awry in conditions that cause developmental delays in humans, and may reappear in old age and contribute to synaptic loss during Alzheimer’s disease, Bear said.
In mice, the MIT researchers found, even one day of deprivation from one eye starts the shift to dominance of the uncovered eye. But injecting the mice with a cannabinoid receptor blocker halted the shift in certain brain regions, indicating that cannabinoids play a key role in early synaptic development.
Blocking cannabinoids receptors could thwart this developmental process, the researchers said.
ref: http://web.mit.edu/newsoffice/2008/bear-obesity-0507.html
