Abstract
The melanocortin system is one of the most important neuronal pathways involved in the regulation of food intake and is probably the best characterized. Agouti-related peptide (AgRP) and proopiomelanocortin (POMC) expressing neurons located in the arcuate nucleus of the hypothalamus are the key elements of this system. These two neuronal populations are sensitive to circulating molecules and receive many excitatory and inhibitory inputs from various brain areas. According to sensory and metabolic information they integrate, these neurons control different aspects of feeding behavior and orchestrate autonomic responses aimed at maintaining energy homeostasis. Interestingly, composition and abundance of pre-synaptic inputs onto arcuate AgRP and POMC neurons vary in the adult hypothalamus in response to changes in the metabolic state, a phenomenon that can be recapitulated by treatment with hormones, such as leptin or ghrelin. As described in other neuroendrocrine systems, glia might be determinant to shift the synaptic configuration of AgRP and POMC neurons. Here, we discuss the physiological outcome of the synaptic plasticity of the melanocortin system, and more particularly its contribution to the control of energy balance. The discovery of this attribute has changed how we view obesity and related disorders, and opens new perspectives for their management.
Highlights
Brain plasticity refers to the natural capacity of the brain to modify its structure and function through experience
The first is based on selective ablation of Agouti-related peptide (AgRP) neurons in adult mice. This procedure reduces the GABAergic tone from AgRP neurons within the parabrachial nucleus (PBN) of the hindbrain, a visceral and taste-sensing area, which leads to cessation of feeding and to death by starvation [53,54,55]
Synaptic plasticity of the melanocortin system is currently considered as an adaptive process activated by huge variations in circulating hormones that can be seen during extreme metabolic circumstances, such as 3-day overfeeding and 24-h fasting in rodents
Summary
Brain plasticity refers to the natural capacity of the brain to modify its structure and function through experience. This attribute relies on the property of neurons to adjust their responsiveness, molecular content, and connections as a result of activity. Neurotransmission in numerous neuronal circuits located in the hypothalamus varies in response to changes within the body and in the environment. This Review focuses on the structural forms of synaptic plasticity in the melanocortin system of the hypothalamus, one of the main neuronal circuits that control appetite and energy homeostasis. Plasticity of brain feeding circuits circuit might compromise its function and confer risk for obesity and related disorders
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
