GHRP-6
Growth Hormone Releasing Peptide-6, Growth hormone-releasing hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Effects of ghrelin on gastric distention sensitive neurons in the arcuate nucleus of hypothalamus and gastric motility in diabetic rats.
Xu. Luo L; Qu. Zhuling Z; Guo. Feifei F; Pang. Mingjie M; Gao. Shengli S; Zhu. Hai H; Gu. Fang F; Sun. Xiangrong X
Key Findings
- Ghrelin excites gastric‑distention excitatory neurons and inhibits inhibitory neurons in the arcuate nucleus.
- Microinjection of ghrelin into the arcuate nucleus boosts gastric motility in a dose‑dependent way.
- Diabetic rats show a weaker gastric‑motility response to ghrelin, linked to reduced GHSR‑1a receptor expression.
- Blocking GHSR with antagonists stops ghrelin’s effects on stomach movement.
Practical Outcomes
- For biohackers, the data suggest that ghrelin or ghrelin‑mimicking peptides (like GHRP‑6) could help improve stomach emptying, but effectiveness may drop in metabolic disorders like diabetes. However, the study used direct brain injections in rats, so translating this to oral or sub‑cutaneous use in humans is uncertain. It reinforces the idea that ghrelin pathways influence gut motility, which could be considered when designing protocols for appetite or digestive health, but more human research is needed before concrete dosing recommendations.
Summary
In diabetic rats, giving ghrelin (the hormone that stimulates hunger) directly into a brain area called the arcuate nucleus helped the stomach move food along, but the effect was weaker than in healthy rats because the brain's ghrelin receptors were lower. Ghrelin also changed the activity of specific stomach‑sensing neurons, exciting those that promote movement and silencing those that inhibit it.
Abstract
This study was performed to observe the effects of ghrelin on the activity of gastric distention (GD) sensitive neurons in the arcuate nucleus of hypothalamus (Arc) and on gastric motility in vivo in streptozocin (STZ) induced diabetes mellitus (DM) rats. Electrophysiological results showed that ghrelin could excite GD-excitatory (GD-E) neurons and inhibit GD-inhibitory (GD-I) neurons in the Arc. However, fewer GD-E neurons were excited by ghrelin and the excitatory effect of ghrelin on GD-E neurons was much weaker in DM rats. Gastric motility research in vivo showed that microinjection of ghrelin into the Arc could significantly promote gastric motility and it showed a dose-dependent manner. The effect of ghrelin promoting gastric motility in DM rats was weaker than that in normal rats. The effects induced by ghrelin could be blocked by growth hormone secretagogue receptor (GHSR) antagonist [d-Lys-3]-GHRP-6 or BIM28163. RIA and real-time PCR data showed that the levels of ghrelin in the plasma, stomach and ghrelin mRNA in the Arc increased at first but decreased later and the expression of GHSR-1a mRNA in the Arc maintained a low level in DM rats. The present findings indicate that ghrelin could regulate the activity of GD sensitive neurons and gastric motility via ghrelin receptors in the Arc. The reduced effects of promoting gastric motility induced by ghrelin could be connected with the decreased expression of ghrelin receptors in the Arc in diabetes. Our data provide new experimental evidence for the role of ghrelin in gastric motility disorder in diabetes.
Study Information
pubmed
2013
2013-08-18T00:00:00.000Z
10.1016/j.peptides.2013.08.010
11
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