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Multiple mechanisms in the motor responses of the guinea-pig isolated urinary bladder to bradykinin
| Content Provider | Scilit |
|---|---|
| Author | Maggi, Carlo Alberto Patacchini, Riccardo Santicioli, Paolo Geppetti, Pierangelo Cecconi, Roberto Giuliani, Sandro Meli, Alberto |
| Copyright Year | 1989 |
| Description | Journal: British Journal of Pharmacology 1 Bradykinin (1 nM-1 μm) produced a contraction of bladder strips excised from the dome of the guinea-pig urinary bladder, an effect which was greatly enhanced by removal of the mucosal layer or by thiorphan (10 μm). All subsequent experiments were performed in mucosa-free strips and in the presence of thiorphan. 2 In carbachol (5 μm)-contracted strips, bradykinin produced a concentration (1 nM-1 μm)-dependent transient relaxation. 3 Kallidin was slightly more potent than bradykinin in producing a contraction and a relaxation of the carbachol-induced tone. By contrast, $[des-Arg^{9}$]-bradykinin, a selective $B_{1}$ receptor agonist was barely effective up to 1 μm. 4 The contractile response to bradykinin was: (a) unaffected by either tetrodotoxin (1 μm), in vitro capsaicin desensitization (10 μm for 30 min) or apamin (0.1 μm); (b) antagonized by indomethacin (5 μm), the prostaglandin receptor antagonist SC-19220 (100 μm) or the $B_{2}$ receptor antagonist $[D-Arg^{0}$, $Hyp^{3}$, $Thi^{5,8}$, $Phe^{7}$]-bradykinin (10 μm) and (c) almost abolished by nifedipine (1 μm). 5 The antagonism of the contractile response to bradykinin produced by indomethacin and SC-19220 was non-additive while that produced by indomethacin and the $B_{2}$ receptor antagonist was additive. 6 The relaxant response to bradykinin was unaffected by tetrodotoxin, in vitro capsaicin desensitization or indomethacin but antagonized in a competitive manner by the $B_{2}$ receptor antagonist. Further, this response was abolished by apamin (0.1 μm) but unaffected by glibenclamide (1 μm). 7 Bradykinin (10 μm) produced a consistent release of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) but not substance P-LI from the guinea-pig bladder muscle. CGRP-LI release by bradykinin was greatly reduced in bladders exposed to indomethacin. $[des-Arg^{9}$]-bradykinin (10 μm) was ineffective. 8 We conclude that: (a) bradykinin-induced contraction involves activation of both $B_{2}$ receptors and prostanoid synthesis, via distinct mechanisms which act by inducing calcium influx via nifedipine-sensitive channels; (b) bradykinin-induced relaxation involves activation of $B_{2}$ receptors and opening of apamin-sensitive potassium channels; (c) bradykinin stimulates sensory nerves in this tissue largely via prostanoid production. |
| Related Links | http://europepmc.org/articles/pmc1854696?pdf=render https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1476-5381.1989.tb12636.x |
| Ending Page | 629 |
| Page Count | 11 |
| Starting Page | 619 |
| e-ISSN | 14765381 |
| DOI | 10.1111/j.1476-5381.1989.tb12636.x |
| Journal | British Journal of Pharmacology |
| Issue Number | 2 |
| Volume Number | 98 |
| Language | English |
| Publisher | Wiley-Blackwell |
| Publisher Date | 1989-10-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: British Journal of Pharmacology Guinea Pig |
| Content Type | Text |
| Resource Type | Article |
