Do β3-adrenergic receptors play a role in guinea pig detrusor smooth muscle excitability and contractility?

Serge A Y Afeli, Kiril L. Hristov, Georgi Petkov

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

In many species, β3-adrenergic receptors (β3-ARs) have been reported to play a primary role in pharmacologically induced detrusor smooth muscle (DSM) relaxation. However, their role in guinea pig DSM remains controversial. The aim of this study was to investigate whether β3-ARs are expressed in guinea pig DSM and to evaluate how BRL37344 and L-755,507, two selective β3-AR agonists, modulate guinea pig DSM excitability and contractility. We used a combined experimental approach including RT-PCR, patch-clamp electrophysiology, and isometric DSM tension recordings. β3-AR mRNA message was detected in freshly isolated guinea pig DSM single cells. BRL37344 but not L-755,507 caused a slight decrease in DSM spontaneous phasic contraction amplitude and frequency in a concentration-dependent manner. In the presence of atropine (1 μM), only the spontaneous phasic contractions frequency was inhibited by BRL37344 at higher concentrations. Both BRL37344 and L-755,507 significantly decreased DSM carbachol-induced phasic and tonic contractions in a concentration-dependent manner. However, only BRL37344 inhibitory effect was partially antagonized by SR59230A (10 βM), a β3-AR antagonist. In the presence of atropine, BRL37344 and L-755,507 had no inhibitory effect on electrical field stimulation-induced contractions. Patch-clamp experiments showed that BRL37344 (100 βM) did not affect the DSM cell resting membrane potential and Kβ conductance. Although β3-ARs are expressed at the mRNA level, they play a minor to no role in guinea pig DSM spontaneous contractility without affecting cell excitability. However, BRL37344 and L-755,507 have pronounced inhibitory effects on guinea pig DSM carbachol-induced contractions. The study outlines important DSM β3-ARs species differences.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Renal Physiology
Volume302
Issue number2
DOIs
StatePublished - Jan 1 2012

Fingerprint

Adrenergic Receptors
Smooth Muscle
Guinea Pigs
Carbachol
Atropine
Smooth Muscle Myocytes
Muscle Tonus
Adrenergic Agonists
Messenger RNA
Adrenergic Antagonists
Muscle Relaxation
Electrophysiology
Membrane Potentials
Electric Stimulation
Cell Membrane
Polymerase Chain Reaction

All Science Journal Classification (ASJC) codes

  • Physiology
  • Urology

Cite this

Do β3-adrenergic receptors play a role in guinea pig detrusor smooth muscle excitability and contractility? / Afeli, Serge A Y; Hristov, Kiril L.; Petkov, Georgi.

In: American Journal of Physiology - Renal Physiology, Vol. 302, No. 2, 01.01.2012.

Research output: Contribution to journalArticle

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