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Study Identifies Receptors Connecting Smell to Appetite When Fasting
Posted: February 17, 2014
A study has found that cannabinoid type-1 (CB1) receptors in the brain promote food intake in mice subjected to fasting and hunger by increasing odor detection.
The study, "The endocannabinoid system controls food intake via olfactory processes," published in the journal Nature Neuroscience, indicated that CB1 receptors were abundantly expressed on axon terminals of centrifugal cortical glutamatergic neurons that project to inhibitory granule cells of the main olfactory bulb (MOB).
"Local pharmacological and genetic manipulations revealed that endocannabinoids and exogenous cannabinoids increased odor detection and food intake in fasted mice by decreasing excitatory drive from olfactory cortex areas to the MOB. Consistently, cannabinoid agonists dampened in vivo optogenetically stimulated excitatory transmission in the same circuit," the study said.
Further, it noted that cortical feedback projections to the MOB crucially regulate food intake via CB1 receptor signaling, linking the feeling of hunger to stronger odor processing.