Table 1.
Summary of the neuroprotective effects of ghrelin, des-acyl ghrelin, and synthetic antagonists and agonists of the ghrelin receptor.
| Ghrelin | Des-acyl ghrelin | GHS | Antagonists | |
|---|---|---|---|---|
| Excitotoxicity | Prevents kainic acid and pilocarpine-induced excitotoxicity in hippocampal neurons | Not determined | Prevents glutamate-induced apoptosis in the hypothalamus and cerebellum | Not determined |
| Parkinson’s disease | Increase tyrosine hydroxylase in midbrain and dopamine turnover induced in the striatum. Reduce dopamine cell loss induced by MPTP. Inhibits microglia activation after MPTP administration | Not determined | Not determined | Not determined |
| Stroke and ischemia | Neuroprotection in the forebrain reducing infarct volume and cell death. Protects loss of CA1 and CA3 neurons after IR. Protects oxygen and glucose-deprived cells in hypothalamic neurons. Protects cortical neurons from injury induced by transient focal cerebral IR | Protects hippocampus from IR reducing infarct volume. Protect cortical neurons from injury induced by transient focal cerebral IR | Hexarelin reduces infarct size following focal cerebral ischemia and improves neuronal survival in vitro | Reverses neuroprotection effects of ghrelin, but not of des-acyl ghrelin |
| Epilepsy | Anti-epileptic effects in pentylenetetrazole-injected rats. Decreases oxidative stress in hippocampal neurons. In pilocarpine models of epilepsy attenuates CA1 and CA3 hippocampal neuronal loss. Attenuates kainic acid-induced neuronal death in CA1 and CA3 hippocampal regions. Anticonvulsant effect in animal seizure models | Not determined | Not determined | Not determined |
| Spinal cord injuries | Improves functional recovery by inhibiting apoptosis and enhancing neurogenesis | Not determined | Not determined | Not determined |
| Encephalomyelitis | Reduces severity and levels of pro-inflammatory cytokines and activated microglia | Not determined | Not determined | Not determined |
| Diabetes | Decreases cell death in the anterior pituitary | Not determined | In combination with insulin, GHRP-6 attenuates cell death in hypothalamus and cerebellum | Not determined |
GHRP-6, growth hormone-releasing peptide 6; MPTP IR.