Neurite outgrowth: nootropics and compounds | sci-wiki

EPObis

EPObis is a synthetic dendrimeric peptide designed from the binding Site 1 sequence of human erythropoietin, guided by the crystal structure of the erythropoietin-receptor complex. It binds the erythropoietin receptor and reproduces the cytokine's tissue-protective signaling; in cultured neurons it promotes neurite outgrowth and survival in a receptor-dependent manner. Unlike erythropoietin itself, EPObis is non-erythropoietic, so it activates protective pathways without stimulating red blood cell production, and after systemic administration it crosses the blood-brain barrier into the cerebrospinal fluid. In rodent studies it reduces tumor necrosis factor release from activated macrophages and microglia, delays clinical signs in experimental autoimmune encephalomyelitis, and enhances working memory, marking it as an experimental neuroprotective and anti-inflammatory research peptide.

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Nootropic

Pregnenolone

Pregnenolone (3β-hydroxypregn-5-en-20-one) is an endogenous neurosteroid and the first steroid synthesized from cholesterol, making it the obligatory precursor of every other steroid hormone, including progesterone, dehydroepiandrosterone (DHEA), cortisol, the sex steroids, and the neuroactive metabolites allopregnanolone and pregnenolone sulfate. Once regarded as a metabolically inert intermediate, it is now recognized as a signaling molecule in its own right, most notably as an endogenous negative allosteric modulator of the type-1 cannabinoid receptor (CB1, the principal brain receptor for THC) and as a ligand for microtubule-associated protein 2 (MAP2, a neuronal cytoskeletal scaffolding protein), through which it promotes microtubule assembly and neurite outgrowth. Synthesized de novo in the brain by neurons and glia, it is investigated as an adjunctive treatment for schizophrenia, mood disorders, and cannabis-related conditions, and is sold over the counter as a nootropic and hormonal supplement.

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Nootropic

DHEA Sulfate

DHEA sulfate (DHEAS) is the 3-beta sulfate ester of dehydroepiandrosterone and the most abundant circulating steroid in the human body, present in plasma at concentrations roughly a thousandfold higher than unconjugated DHEA. Synthesized principally in the zona reticularis of the adrenal cortex, it functions as a stable, long-lived reservoir that is interconverted with DHEA and supplies a precursor pool for downstream androgens and estrogens. Within the nervous system it is classified as a neurosteroid (a steroid synthesized in or acting directly upon nervous tissue); it acts as an agonist at the sigma-1 receptor (an intracellular chaperone protein), a positive modulator of the NMDA receptor (a glutamate-gated excitatory ion channel), and a negative allosteric modulator of the GABA-A receptor (the brain's principal inhibitory ion channel), giving it a net excitatory, pro-cognitive neuromodulatory profile. Circulating concentrations fall markedly with age, a decline termed adrenopause that has made DHEAS a widely studied biomarker of adrenal function, cognitive aging, and longevity.

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Nootropic

MAP4343

MAP4343 (3β-methoxypregnenolone) is a synthetic derivative of the endogenous neurosteroid pregnenolone in which the 3β-hydroxyl group is replaced by a methyl ether, developed by the French steroid pharmacologist Étienne-Émile Baulieu and the biotechnology company Mapreg. Unlike classical neurosteroids that modulate ligand-gated ion channels, MAP4343 acts on microtubule-associated protein 2 (MAP2; a structural protein that governs the assembly and stability of neuronal microtubules), where it promotes tubulin polymerization and restores microtubule dynamics. It has been investigated as a novel, mechanistically distinct antidepressant and anti-addiction candidate, showing rapid and durable antidepressant-like effects in rodent and tree shrew stress models and having advanced into early clinical development. As of the mid-2020s it remains an investigational agent without regulatory approval.

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Nootropic

T-817MA

T-817MA, later given the generic name edonerpic maleate, was developed by Toyama Chemical (subsequently absorbed into Fujifilm's pharmaceutical division) as a neurotrophic and neuroprotective small molecule aimed squarely at Alzheimer's disease, but built on a different premise than amyloid-clearing antibodies: promote neurite outgrowth and protect synapses from amyloid-beta toxicity directly. It advanced through multiple Phase II trials in Japan, the US and Europe, including a joint program with the Alzheimer's Disease Cooperative Study, and produced a real biomarker signal, dose-dependent drops in cerebrospinal fluid tau. That biomarker success never translated into a clinical cognitive benefit large enough to justify a Phase III program, and the compound was shelved, joining the long list of tau- and neuroprotection-targeted Alzheimer's candidates that moved the numbers without moving the patient.

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