Growth hormone secretagogue receptor secretagogue receptor is activated, a variety of different intracellular signaling cascades can result, depending on the cell type in which the receptor is expressed. These intracellular signaling cascades include mitogen-activated protein kinase (MAPK)), protein kinase A (PKA), protein kinase B (PKB), also known as AKT), and AMP Activated Protein Kinase (AMPK) cascades. It is well-characterized that activating the growth hormone secretagogue receptor with ghrelin induces an orexigenic state, or general feeling of hunger. However, ghrelin may also play a role in behavioral reinforcement. Studies in animal models, found that food intake increased when ghrelin was specifically administered to just the
Growth hormone secretagogue receptor ventral tegmental area (VTA), a brain area that uses dopamine signaling to reinforce behavior. In fact, the more ghrelin administered, the more food the rodent consumed. This is called a dose-dependent effect. Building on this, it was found that there are growth hormone secretagogue receptors in the VTA and that ghrelin acts on the VTA through these receptors. Current studies, furthermore, suggest that the VTA may contain dimers of GHS-R1a and dopamine receptor type 2 (DRD2). If these two receptors do indeed form dimers, this would somehow link ghrelin signaling to dopaminergic signaling. The growth hormone secretagogue receptor may also