PhenylpiracetamvsPramiracetam

Phenylpiracetam modulates AMPA and NMDA glutamate receptors like other racetams through positive allosteric modulation. The phenyl group confers additional affinity for dopamine (DAT) and norepinephrine (NET) transporters, acting as a weak reuptake inhibitor and increasing synaptic catecholamine availability — providing stimulatory and motivational effects. It binds to α4β2 and α7 nicotinic acetylcholine receptors as a positive allosteric modulator, enhancing cholinergic transmission in the prefrontal cortex and hippocampus. The phenyl moiety improves blood-brain barrier penetration via increased lipophilicity and potentially P-glycoprotein substrate properties. Downstream effects include enhanced CREB phosphorylation and BDNF expression. The combination of glutamatergic, dopaminergic, noradrenergic, and cholinergic modulation produces synergistic cognitive enhancement.

Pramiracetam increases high-affinity choline uptake (HACU) in the hippocampus via potentiation of the choline transporter (CHT1), similar to but 15-30x more potent than coluracetam — dramatically increasing acetylcholine synthesis and release. It modulates AMPA glutamate receptors through positive allosteric modulation, enhancing excitatory neurotransmission. Pramiracetam increases neuronal nitric oxide synthase (nNOS) activity, elevating nitric oxide (NO) production and inducing cerebral vasodilation via cGMP-dependent pathways, thereby enhancing cerebral blood flow and oxygen delivery. The emotional flattening effect suggests significant modulation of prefrontal cortex activity, possibly through excessive cholinergic tone in limbic-prefrontal circuits or reduced dopaminergic/emotional salience signaling. It may also modulate sigma-1 receptor activity.