The Scripps Research team decided to take a fresh look at the whole question, and set out to conduct a new physiological study specifically looking for signs of the missing CB1 receptors in the central amygdala.
"There wasn't much physiology done before this," said Roberto. "There were a lot of behavioral studies, but very few on physiology and, aside from the 2001 study, none on the physiology in the central amygdalathis brain region that is so important for drugs of abuse."
Back on Track
Using electrophysiological techniques in brain slices to test the response of brain cells from the rat central amygdala, the scientists indeed found compelling evidence that CB1 receptors were active there.
The cells responded to a substance (agonist) mimicking the action of endocannabinoids in the brain. Up to a point, the more of the agonist the scientists applied, the bigger the effect. An inhibitor (antagonist) reversed this response.
"We saw a big and consistent physiological effect," said Roberto. "It was beautiful. The receptor had to be there or otherwise it wouldn't have worked."
With this major milestone achieved, the researchers extended their investigation to their primary area of interestthe brain's response to alcohol. Alcohol abuse can lead to devastating consequences for individuals and families. It is also associated with direct and indirect public health costs estimated to be in the hundreds of billions of dollars yearly in the United States alone.
To learn more about the effect of alcohol on the biology of the brain, the scientists focused on the transmission of one particular neurotransmitter called gamma amino butyric acid (GABA). GABA is the main inhibitory neurotransmitter in the brain, and neurons in every b
|Contact: Keith McKeown|
Scripps Research Institute