Ghrelin rat has been used for intraperitoneal injections, and microinjections in rats to study its effects on celiac disease, and passive avoidance learning (PAV) and spatial learning, respectively. It has also been used for intracerebroventricular injection in rats to study its influence on penicillin-induced epileptiform activity in rat.
Ghrelin is a gut-brain orexigenic peptide that functions in hunger signaling. This peptide is prominently synthesized by stomach and transported to brain. However, a specific subset of hypothalamic neurons also produces this peptide. It is expressed in gastrointestinal tract, hypothalamic arcuate nucleus, pituitary, kidney, liver, heart, lung and adipose tissue This peptide is composed of 28 amino acids, and its Ser3 residue is N-octanoylated.
Ghrelin acts as a ligand for G-protein coupled receptor, GHS-R1A (growth hormone secretagogue receptor), and controls energy utilization and feeding. This peptide is involved in enhancing the value of rewarding foods, drugs and alcohol. In rats with diabetes, the expression of ghrelin increased as a result of cachexia. In rats with ovariectomy, the expression of this peptide decreased in the endometrium. This peptide controls cognitive functions and has neuroprotective roles in neurodegenerative disorders. In cultured cortical neuronal networks, ghrelin increases the rate of synapse formation and activity development.
