Differential sensitivity to phenoxybenzamine alkylation among types of neurokinin binding sites.
The effect of phenoxybenzamine (PBZ) treatment of crude membranes was examined on binding to neurokinin/tachykinin NK-1, NK-2, and NK-3 binding sites. PBZ in concentrations up to 300 microM resulted in only a slight reduction in Bmax in binding of iodinated substance P to NK-1 sites in rat submaxillary gland and in rat urinary bladder. PBZ in concentrations as low as 30 microM resulted in a decrease in Bmax or in affinity in binding of iodinated neurokinin A (substance K) to NK-2 sites in hamster bladder and in rat bladder, and a decrease in affinity in binding of iodinated eledoisin to NK-3 sites in rat cerebral cortex. The results indicate a parallelism in differential sensitivity to PBZ alkylation between neurokinin biological receptors and neurokinin ligand binding sites.
D000477:Alkylating Agents / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D006224:Cricetinae; D066298:In Vitro Techniques; D007700:Kinetics; D010643:Phenoxybenzamine / Q000494:pharmacology*; D011869:Radioligand Assay; D051381:Rats; D013363:Submandibular Gland / Q000378:metabolism; D001743:Urinary Bladder / Q000378:metabolism
D000477:Alkylating Agents; D010643:Phenoxybenzamine