[125I]neurokinin A labels pharmacologically distinct populations of NK2 binding sites in hamster and rabbit urinary bladder.
The pharmacological profile of NK2 binding sites has been characterised in homogenates of rabbit urinary bladder and compared with that present in homogenates of hamster bladder. In both species, [125I]neurokinin A-specific binding to urinary bladder membranes was displaced by neurokinin A and the NK2 agonist [beta-Ala8]neurokinin A-(4-10) whilst the NK1 ligands [Sar9,Met(O2)11]substance P and (+/-)-CP-96,345, and the NK3 agonist, senktide, were only weak displacers or ineffective. At rabbit NK2 sites, the rank order of affinity of NK2 receptor-selective antagonists was; MEN 10,376 > MEN 10,207 > L-659,877 >> R 396. In contrast, the rank order of displacement of [125I]neurokinin A-specific binding to hamster bladder membranes was: L-659,877 > R 396 > MEN 10,376 > MEN 10,207. These data demonstrate that [125I]neurokinin A binds to pharmacologically distinct NK2 binding sites in hamster and rabbit urinary bladder.
Parke-Davis Neuroscience Research Centre, Addenbrookes Hospital Site, Cambridge, UK.
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D000595:Amino Acid Sequence; D000818:Animals; D006224:Cricetinae; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D008647:Mesocricetus; D008969:Molecular Sequence Data; D015288:Neurokinin A / Q000378:metabolism*; D011817:Rabbits; D011869:Radioligand Assay; D018041:Receptors, Neurokinin-2; D017981:Receptors, Neurotransmitter / Q000378:metabolism; D015320:Tachykinins / Q000037:antagonists & inhibitors / Q000494:pharmacology; D001743:Urinary Bladder / Q000378:metabolism*
D007457:Iodine Radioisotopes; D018041:Receptors, Neurokinin-2; D017981:Receptors, Neurotransmitter; D015320:Tachykinins; D015288:Neurokinin A