0000000000355341
AUTHOR
Carsten Sand
The Odd Sibling: Features ofβ3-Adrenoceptor Pharmacology
beta(3)-Adrenoceptor agonists have recently been introduced for the treatment of overactive urinary bladder syndrome. Their target, the beta(3)-adrenoceptor, was discovered much later than beta(1)- and beta(2)-adrenoceptors and exhibits unique properties which make extrapolation of findings from the other two subtypes difficult and the beta(3)-adrenoceptor a less-understood subtype. This article discusses three aspects of beta(3)-adrenoceptor pharmacology. First, the ligand-recognition profile of beta(3)-adrenoceptors differs considerably from that of the other two subtypes, i.e., many antagonists considered as nonselective actually are beta(3)-sparing, including propranolol or nadolol. Man…
Bradykinin Contracts Rat Urinary Bladder Largely Independently of Phospholipase C
Several receptor systems in the bladder causing detrusor smooth muscle contraction stimulate phospholipase C (PLC). PLC inhibition abolishes bladder contraction via P2Y6 but not that via M3 muscarinic receptors, indicating a receptor-dependent role of PLC. Therefore, we explored the role of PLC in rat bladder contraction by bradykinin. The PLC inhibitor U 73,122 [1-(6-[([17β]-3-methoxyestra-1,3,5[10]-trien-17-yl)-amino]hexyl)-1H-pyrrole-2,5-dione] did not affect the bradykinin response to a significantly greater degree than its inactive analog U 73,343 [10 μM each; 1-(6-[-([17β]-3-methoxyestra-1,3,5[10]-trien-17-yl)-amino]hexyl)-2,5-pyrrolidinedione], whereas the phospholipase D inhibitor b…