February 11, 2014
Brain Mechanism Discovered Linking Food Smell And How Much We Eat
[ Watch the Video: Does Your Nose Make You Eat More? ]
Lee Rannals for redOrbit.com - Your Universe OnlineScientists, publishing a paper in the journal Nature Neuroscience, say that the type 1 cannabinoid receptor in the olfactory bulb in the brain could be causing you to eat more at the smell of food.
The team set out to discover why smelling food causes an increase in food intake when in a state of hunger or fasting. The team said they found that smelling food is linked to the type 1 cannabinoid receptor. They also found that these receptors could be used by pharmacological researchers to treat eating disorders.
Before this study, the cannabinoid system was linked to the phenomena that hunger increases the sense of smell and food intake. However, the new research provides more light into how this system governs the connection.
“The level of endogenous cannabinoids in mammal brains is known to be increased by abstaining from food, or fasting, and the cannabinoid system is known to be an important component in regulating energy balance,” Perdro Grandes, a researcher in the UPV/EHU’s department of Neurosciences, and co-leader of the research together with Giovanni Marsicano, a researcher at the University of Bordeaux, said in a statement. “In situations of hunger, anandamide, which is a specific type of endogenous cannabinoid, is synthesized and acts on a specific receptor, CB1. These receptors are located at certain nerve endings in the olfactory bulb, whose function is to regulate excitatory synaptic transmission.”
He added that when cannabinoids act on the CB1 receptors in the bulb, a reduction in the excitatory communication come in from olfactory areas in the cerebral cortex takes place.
“As a result, all the intrinsic functions that are on the level of the olfactory bulb are enhanced. So, for example, the cells that pick up smell transmit better, and therefore, the perception of smell is greater,” Grandes explained.
The team found that these phenomena are not unleashed by the endogenous cannabinoids alone, but are in one type of cannabinoid that is also an active component of marijuana.
“One type of exogenous cannabinoid, THC, which is the psychoactive component of cannabis, also led to the increase in the perception of the sense of smell and appetitewhen [sic] injected into these mice.Of [sic] course this effect always takes place in fasting conditions; in the cases in which the mice had eaten their fill, this mechanism did not kick in,” Grandes said.
“In people with anorexia we could stimulate intake by enhancing these mechanisms.And [sic] by contrast, in cases of obesity, the aim would be to try and reduce the function of these CB1 receptors to reduce the perception of smell and thus get these individuals to eat less when they are hungry,” Grandes concluded.