FIGURE 8.
Role of gasotransmitters on ghrelin release and its physiological functions. Solid lines are clear evidence–based on blockers and substrate administration. Dotted lines represent first evidence for the presence of the pathway. The amino acid l-cysteine, which is a H2S donor, suppresses ghrelin release from the stomach. Ghrelin promotes the release of GH via activation of the NOS/NO/GC/cGMP-signaling pathway. Ghrelin also promotes feeding behavior and stimulates gastric motility and acid secretion via the NO-pathway. No direct evidence is found to date for the involvement of NO in the ghrelin-glycemic effect. Ghrelin protects the gastric mucosa, by stimulation of the blood flow and hyperemia mediated by NO. CO is also involved in the ghrelin-mediated gastroprotection. NO, Nitric oxide; CO, Carbon monoxide; H2S, Hydrogen sulfide; GH, Growth hormone; NOS, Nitric oxide synthase; GC, Guanylyl cyclase; cGMP, Cyclic guanosine monophosphate.