BIBP3226 TFA (BIBP 3226) is a highly potent and selective non-peptide neuropeptide Y Y1 receptor (NPY1R) antagonist with Ki of 7 nM. BIBP3226 potently blocks (pA2 = 7.36) the contractile effect of neuropeptide Y in the rabbit saphenous vein, a Y1 receptor bioassay and demonstrated nM affinity for Y1/[125I][Leu31,Pro34]peptide YY binding sites. BIBP3226 (BIBP 3226) does not significantly compete for Y2/[125I]peptide YY-(3-36) binding sites in rat and human brain homogenates. BIBP3226 (BIBP 3226) antagonizes the NPY Y1 receptor-mediated decrease in the twitch response in the rabbit vas deferens preparation with a pKb value of 6.98. BIBP3226 (BIBP 3226) inhibits NPY-induced increase in blood pressure in the pithed rat.
