GEBR-7b

GEBR-7b is a **selective phosphodiesterase-4D (PDE4D) inhibitor** structurally related to rolipram. It is a small molecule developed to enhance cerebral cyclic AMP (cAMP) signaling by specifically inhibiting PDE4D, one of the main cAMP-catabolizing enzymes in the brain[1][2][4][5][8]. In animal studies, GEBR-7b increases hippocampal cAMP levels and significantly improves spatial and object memory performance in rodents, with greater potency and fewer emetic side effects than earlier PDE4 inhibitors like rolipram[1][5][7][8]. Unlike non-selective PDE4 inhibitors, GEBR-7b shows high selectivity for PDE4D over other isoforms (PDE4A, PDE4B, PDE4C), and at effective doses does not induce nausea or emesis-like effects in rodents[1][5][7]. Its principal research indication is for **memory impairment and cognitive deficits**, based on preclinical efficacy[1][7][8].