title: Substance P and neurokinins as stimulants of the human isolated urinary bladder.
abstract: Neurokinins are active stimulants of the human isolated urinary bladder. In a preliminary study, performed on bladders taken from four donors, we attempted the characterization of neurokinin receptors. It was shown that neurokinin A is more active than neurokinin B and substance P. Neurokinin receptors selective agonists were also tested and it was found that the most active compound was the NK-A selective agonist, [Nle10]NKA 4-10: A substance P antagonist was able to reduce the effect of neurokinin A but its affinity was rather low. This suggests that the receptor mediating the contraction of the human urinary bladder to neurokinins is of the NK-A (NK2) type. The action of neurokinins on the human urinary bladder appears to be a direct one and mediated by specific receptors different from those of other agents. On the contrary, kinins were found to be active through a new mechanism which was not influenced by either anti-B1 or anti-B2 receptor antagonists.
mesh_terms: D000328:Adult; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D015288:Neurokinin A; D015287:Neurokinin B; D009479:Neuropeptides / Q000378:metabolism / Q000494:pharmacology*; D018041:Receptors, Neurokinin-2; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000378:metabolism; D013373:Substance P / Q000494:pharmacology*; D001743:Urinary Bladder / Q000187:drug effects* / Q000502:physiology
chemical_list: D009479:Neuropeptides; D018041:Receptors, Neurokinin-2; D017981:Receptors, Neurotransmitter; D013373:Substance P; D015288:Neurokinin A; D015287:Neurokinin B