Thickness is not always due to a good appetite
Based on the results obtained by scientists at the University of California, working under the guidance of Dr. Kaveh Ashrafi, a person's habitual diet is not a determining factor of his thinness or excess weight. Experiments on roundworms Caenorhabditis elegans have shown that, despite the fact that both hunger and body fat depend on the level of serotonin in the nervous system, the effect of this neurotransmitter on appetite and the use of absorbed calories is mediated by various independent mechanisms.
The results obtained indicate that the nervous system is a key regulator that coordinates all energy-related processes through various molecular mechanisms. The nervous system makes decisions about the state of the body, which leads to various effects on behavior, reproduction, growth and metabolism. These effects are interrelated, but they are not consequences of each other. This does not mean that the nutrition system does not matter for maintaining body weight, but that the control of the nervous system over the distribution of fat is not related to nutrition.
If the results obtained on worms prove to be valid for humans, which is very likely, given the ancient evolutionary origin of serotonin, they may have important clinical significance. From a clinical point of view, this discovery means that it is possible to develop therapeutic strategies for manipulating metabolism regardless of the regime and nature of nutrition, while modern methods of combating obesity are based on changing these parameters.
Fat metabolism in the first approximation is a relatively simple balance between the intake and consumption of energy, but the physiology of this process is quite complex. Therefore, C.elegans nematodes were chosen as the object of the study.
They found that in worms, nutrition management through serotonin occurs with the participation of receptors that are not involved in fat metabolism. The effect of this neurotransmitter on fat metabolism is mediated by another system of connections between neurons, whose receptors send signals to trigger the breakdown of fats. By-products of this process go through a "full cycle" and affect appetite.
In both C.elegans and mammals, high levels of serotonin lead to a decrease in body fat, and low levels lead to fat accumulation. However, there is a difference: in C.elegans, an increase in serotonin levels stimulates appetite and reduces the volume of fat deposits, while in humans it suppresses appetite and also breaks down fat deposits.
Since the amount of food consumed in C.elegans directly depends on its availability, the effect of serotonin on fat metabolism and food intake is consistent with the role of this neurotransmitter as a sensor of food availability.
Despite the differences and taking into account the participation of the serotonin-mediated mechanism in maintaining energy balance in many species, the authors suggest that the human analogues of the genes they identified that control fat metabolism regardless of diet have similar functions in the human body.
Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of ScienceDaily
06.06.2008