cx516

CX516 is a small molecule nootropic and the first compound in the "ampakine" class. It acts as a positive allosteric modulator of the AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor, enhancing glutamatergic neurotransmission by binding to an allosteric site on the AMPA receptor channel complex. This action prolongs channel opening in response to glutamate, slows receptor deactivation, increases excitatory postsynaptic potential duration, and improves hippocampal long-term potentiation (LTP)[1][2][3][5]. CX516 was developed collaboratively by Cortex Pharmaceuticals (now RespireRx Pharmaceuticals), Shire, and Servier[3][7]. It was investigated for cognitive enhancement in conditions such as Alzheimer's disease (under the brand name Ampalex), schizophrenia, ADHD, autism spectrum disorder, fragile X syndrome, and mild cognitive impairment[3][5][7]. Despite promising preclinical results and good safety profile in humans[4], clinical trials were disappointing due to low potency and short half-life (~45 minutes), leading to discontinuation of its development for therapeutic use[3][4].

Brand names

ampalex

Other names

ampakine cx 516