data + articles · 2 listed
newest 2017spec sheet8 rows
tc299423 is an experimental (targacept) small-molecule nicotinic agonist with an alpha6-preferring profile; it activates alpha6beta2* receptors at ec50 ~30-60 nm (about 2.5-fold over alpha4beta2), is orally bioavailable with a clean off-target screen, produces alpha6*-mediated reward in place-preference tests, but did not block nicotine self-administration; a research tool showing small molecules can preferentially target alpha6*, not a medicine.
- a namable, orally bioavailable small-molecule agonist with an alpha6-preferring profile (EC50 ~30-60 nM, ~2.5x over alpha4beta2)
- clean off-target profile (no major hits on a 70-target panel)
- useful in-vivo tool where peptide conotoxins can't go (brain penetration)
- demonstrated alpha6*-mediated reward (conditioned place preference) via alpha6(non-alpha4)beta2 receptors
Mechanism
tc299423 is an experimental small-molecule , a pyrimidine-hexahydroazocine from targacept, developed as a tool to preferentially activate alpha6beta2-containing nicotinic receptors, the subtype that gates release on catecholaminergic terminals. according to pubmed, wall et al characterized it across binding, electrophysiology and neurotransmitter-release assays and found an ec50 of roughly 30-60 nm at alpha6beta2* receptors in both patch-clamp recordings and [3h]-dopamine release, about 2.5-fold more potent than at alpha4beta2 and much more potent than at the ganglionic alpha3beta4 subtype (doi 10.3389/fphar.2017.00641). the honest characterization is 'alpha6-preferring' rather than 'alpha6-selective'; it still activates alpha4beta2, just less potently, unlike the far more selective conotoxins. its practical advantage over those peptides is that it is a small molecule with real after intraperitoneal or oral dosing and a clean off-target profile (no major activity across a 70-target screen), which lets it be used in living animals where conotoxins cannot easily go. in vivo, tc299423 revealed alpha6*-linked behaviors: using gain-of-function alpha6 (alpha6l9's) mice it elicited alpha6beta2*-mediated locomotor responses at low doses and produced conditioned place preference (a reward measure), strongly in alpha6l9's mice and modestly in wild-type mice, through a mechanism probably involving alpha6(non-alpha4)beta2 receptors. it also evoked nicotine-like antinociception in a hot-plate test and reduced marble burying similarly to nicotine (an anxiolytic-like readout). notably, despite being an alpha6-preferring agonist, it did not suppress nicotine self-administration in rats at the doses tested, so it did not act as a substitution therapy in that model. its role in the alpha6 toolkit is as the agonist counterpart to the conotoxins (mii, pia, txib) and the positive modulator an6001; having agonist, pam and selective-antagonist tools all directed at the same subtype is what enables researchers to interrogate alpha6* function from multiple directions. the honest status is preclinical: tc299423 is a research compound with no clinical development or human data, valued as an orally bioavailable, alpha6-preferring agonist for in-vivo studies, not a medicine or supplement.
receptor fingerprint
Alpha6beta2* (a6b2-containing)agonist (a6-preferring)
Striatal [3H]- releaseevokes (a6b2*-mediated)
Alpha4beta2 (a4b2)agonist (less potent than at a6b2*)
Alpha3beta4 (a3b4)agonist (much weaker)
Off-target binding (70-target panel)no major off-target activity
Safetyrisks and cautions, not medical advice
TC299423 is a preclinical research agonist for beta2-containing nicotinic acetylcholine receptors, with an apparent modest preference for alpha6beta2 over alpha4beta2 subtypes; it has been studied only in vitro and in mice and has no human safety data whatsoever. In animal work it produced nicotine-like antinociceptive and anxiolytic-type behavioral effects, which implies it engages the same nicotinic pathways that in humans can drive nausea, dizziness, and cardiovascular activation, but none of this is documented clinically for the compound itself. There are no established doses, contraindications, toxicology, or adverse-event records in humans. It should be treated strictly as an experimental laboratory tool of unknown safety, not a characterized drug.
Subjective profileweighing the evidence above
A research tool, full stop. It usefully showed that a small molecule can preferentially hit alpha6 nicotinic receptors where peptide toxins cannot reach, but it produced reward in animals without reducing nicotine self-administration, and it has never been given to a human.
Resources
This entry is here for reference.
Research
- 1.TC299423, a Novel Agonist for Nicotinic Acetylcholine Receptors
- 2.Striatal alpha6* nicotinic acetylcholine receptors: potential targets for Parkinson's disease therapy
2 listed here; entry last updated July 2026
Reviews
My notesprivate to this device
FAQ
what is tc299423?
it's a small-molecule nicotinic agonist (a pyrimidine-hexahydroazocine, from targacept) developed as a tool to activate alpha6beta2-containing nicotinic receptors. according to pubmed, wall et al reported it activates alpha6beta2* receptors with an ec50 around 30-60 nm and is about 2.5-fold more potent there than at alpha4beta2, with much weaker activity at the ganglionic alpha3beta4 subtype (doi 10.3389/fphar.2017.00641). it's one of the few namable, orally bioavailable small-molecule agonists with an alpha6-preferring profile.
is it truly alpha6-selective?
'alpha6-preferring' is the honest word, not 'alpha6-exclusive'. it's roughly 2.5-fold more potent at alpha6beta2* than at alpha4beta2, so it does hit alpha4beta2 too, just less potently, and it's much weaker at alpha3beta4. that's a meaningful preference for a small molecule (the peptide conotoxins are far more selective), and combined with a clean 70-target off-target screen it makes tc299423 a useful in-vivo agonist tool for alpha6* biology.
what did it show about alpha6 and reward?
that activating alpha6* can be rewarding. wall et al found tc299423 produced conditioned place preference (a reward readout), strongly in alpha6-hypersensitive (alpha6l9's) mice and modestly in wild-type mice, through a mechanism probably involving alpha6(non-alpha4)beta2 receptors (doi 10.3389/fphar.2017.00641). that fits the broader picture of alpha6* receptors as gatekeepers of dopamine-driven reward.
does it block nicotine addiction?
no, and the authors were candid about it. despite being an alpha6-preferring agonist, tc299423 did not suppress nicotine self-administration in rats at the doses tested, so it didn't behave like a substitution therapy in that model (doi 10.3389/fphar.2017.00641). it also produced nicotine-like antinociception (pain relief) and anxiolytic-like effects on marble burying, so its in-vivo profile overlaps with nicotine's in several domains.
how is it different from the alpha6 conotoxins and an6001?
it's the agonist in the toolkit. the conotoxins (mii, pia, txib) block alpha6* receptors; an6001 is a positive modulator that amplifies the natural signal; tc299423 directly activates alpha6* (and, less potently, alpha4beta2). having an agonist, a pam and selective antagonists all pointed at the same subtype is exactly what lets researchers probe alpha6* function from every direction.
is it a drug people can take?
no; it's a research compound with no clinical development or human data. its value is as an orally/ip bioavailable small-molecule agonist for studying alpha6* receptors in living animals, which peptide toxins can't easily do because they don't reach the brain well. it belongs in the lab, and it's included here as a namable alpha6-preferring small-molecule agonist, not as a supplement.
so what's the honest takeaway?
tc299423 is a clean, orally bioavailable, alpha6-preferring nicotinic agonist (ec50 ~30-60 nm at alpha6beta2*, ~2.5x over alpha4beta2) that's proven useful for in-vivo alpha6* studies; it's rewarding in place-preference tests but didn't block nicotine self-administration. it's a research tool that, alongside an6001, shows small molecules can preferentially target alpha6* receptors, not a medicine.