Activity of nonpeptide tachykinin antagonists on neurokinin a induced contractions in dog urinary bladder.
PURPOSE: There is abundant evidence indicating that tachykinin (TK) containing sensory nerves (C-fibers) play an important role in neural regulation of reflex micturition in mammals. Desensitization of urinary bladder C-fibers with resiniferatoxin ameliorates bladder hyperreflexia and incontinence and supports a similar role for C-fibers in man. TK-induced contraction of isolated human urinary bladder smooth muscle appears to be exclusively neurokinin NK2-receptor mediated. Dog urinary bladder contractility to a series of TK-receptor agonists also suggests a predominance of NK2-receptor activation by tachykinins and indicates the dog may provide a useful model for the development of pharmacotherapy for bladder hyperreflexia. MATERIALS AND METHODS: We evaluated the activity of the nonpeptide NK-receptor selective antagonists SR 48968 (NK2), SB 223412 (NK3) and CP 99994 ( NK1) against neurokinin A (NKA)- induced contractions in isolated dog urinary bladder strips to determine the NK-receptor type which mediates contractile responses to NKA. The dual NK1 and NK2 antagonist MDL 103392 was also tested in this preparation. RESULTS: NKA-induced contractions (pD2 = 8.0) were dose dependently blocked by SR 48968 (pA2 = 8.2 +/- 0.2) while CP 99994 (1.0 microM) and SB 223412 (1.0 microM) were inactive. MDL 103392 was a weak functional antagonist (pKb = 6.1 +/- 0.1) of NKA. CONCLUSIONS: Relative activities of SR 48968, CP 99994 and SB 223412 confirm that the NK2-receptor is the mediator of NKA-induced contractions of dog urinary bladder smooth muscle.[1]References
- Activity of nonpeptide tachykinin antagonists on neurokinin a induced contractions in dog urinary bladder. Rizzo, C.A., Hey, J.A. J. Urol. (2000) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg