Abstract
The potential role of A1 adenosine receptors in modulating neuromuscular transmission in the detrusor muscle of the urinary bladder has been tested in human and murine preparations with the intent to determine the viability of using adenosine receptor agonists as adjuncts to treat overactive bladder. In human detrusor muscle preparations, contractile responses to electrical field stimulation were inhibited by the selective A1 adenosine receptor agonists 2-chloro-N6-cyclopentyladenosine, N6-cyclopentyladenosine (CPA), and adenosine (rank order of potency: 2-chloro-N6-cyclopentyladenosine > CPA > adenosine). Pretreatment with 8-cyclopentyl-3-[3-[[4(fluorosulphonyl)benzoyl]oxy]propyl]-1-propylxanthine, an irreversible A1 antagonist, blocked the effects of CPA, thus confirming the role of A1 receptors in human detrusor preparations. In murine detrusor muscle preparations, contractions evoked by electrical field stimulation were reduced by CPA or adenosine. Amplitudes of the P2X purinoceptor–mediated excitatory junctional potentials (EJPs) recorded with intracellular microelectrodes were reduced in amplitude by CPA and adenosine with no effect on the spontaneous EJP amplitudes, confirming the prejunctional action of these agents. 8-Cyclopentyltheophylline, a selective A1 receptor antagonist, reversed the effects of CPA on EJP amplitudes with no effect of spontaneous EJPs, confirming the role of A1 receptors in mediating these effects.
Footnotes
- Received August 21, 2015.
- Accepted November 2, 2015.
This research was supported by the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases [Grant 1R01DK095775], Northwestern University Feinberg School of Medicine, and the Southern Illinois University Urology Endowment Fund.
- Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics
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