Inositol trisphosphate‐dependent Ca2+ stores and mitochondria modulate slow wave activity arising from the smooth muscle cells of the guinea pig prostate gland
- 31 March 2009
- journal article
- Published by Wiley in British Journal of Pharmacology
- Vol. 156 (7), 1098-1106
- https://doi.org/10.1111/j.1476-5381.2009.00130.x
Abstract
Changes in smooth muscle tone of the prostate gland are involved in aetiology of symptomatic prostatic hyperplasia, however the control mechanisms of prostatic smooth muscle are not well understood. Here, we have examined the role of internal Ca(2+) compartments in regulating slow wave activity in the guinea pig prostate. Standard intracellular membrane potential recording techniques were used. The majority (89%) of impaled cells displayed 'slow wave' activity. Cyclopiazonic acid (10 micromol.L(-1)) transiently depolarized (3-9 mV) the membrane potential of the prostatic stroma and transiently increased slow wave frequency. Thereafter, slow wave frequency slowly decreased over 20-30 min. Ryanodine transiently increased slow wave frequency, although after 30 min exposure slow wave frequency and time course returned to near control values. Caffeine (1 mmol.L(-1)) reduced slow wave frequency, accompanied by membrane depolarization of about 8 mV. Blockade of inositol trisphosphate receptor (IP(3)R)-mediated Ca(2+) release with 2-aminoethoxy-diphenylborate (60 micromol.L(-1)) or Xestospongin C (3 micromol.L(-1)) or inhibiting phospholipase C and IP(3) formation using U73122 (5 micromol.L(-1)) or neomycin (1 and 4 mmol.L(-1)) reduced slow wave frequency, amplitude and duration. The mitochondrial uncouplers, p-trifluoromethoxy carbonyl cyanide phenyl hydrazone (1-10 micromol.L(-1)), carbonyl cyanide m-chlorophenylhydrazone (1-3 micromol.L(-1)) or rotenone (10 micromol.L(-1)), depolarized the membrane (8-10 mV) before abolishing electrical activity. These results suggest that slow wave activity was dependent on the cyclical release of Ca(2+) from IP(3)-controlled internal stores and mitochondria. This implies that intracellular compartments were essential in the initiation and/or maintenance of the regenerative contractile activity in the guinea pig prostate gland.This publication has 22 references indexed in Scilit:
- Guide to Receptors and Channels (GRAC), 3rd editionBritish Journal of Pharmacology, 2008
- Ca2+ signalling in urethral interstitial cells of CajalJournal Of Physiology-London, 2006
- Characterization of Spontaneous Depolarizations in Smooth Muscle Cells of the Guinea Pig ProstateJournal of Urology, 2006
- IDENTIFICATION OF C-KIT-POSITIVE CELLS IN THE HUMAN PROSTATE: THE INTERSTITIAL CELLS OF CAJALArchives of Andrology, 2005
- Intracellular Ca2+ regulation in a human prostate stromal cell cultureNeurourology and Urodynamics, 2004
- CHARACTERIZATION OF THE ION CHANNEL CURRENTS IN SINGLE MYOCYTES OF THE GUINEA PIG PROSTATEJournal of Urology, 2004
- Role of Mitochondria in the Generation of Spontaneous Activity in Detrusor Smooth Muscles of the Guinea Pig Bladder.Journal of Urology, 2003
- Interstitial cells: involvement in rhythmicity and neural control of gut smooth muscleJournal Of Physiology-London, 2003
- Regional variation in contribution of myenteric and intramuscular interstitial cells of Cajal to generation of slow waves in mouse gastric antrumJournal Of Physiology-London, 2002
- Modulators of internal Ca2+ stores and the spontaneous electrical and contractile activity of the guinea‐pig renal pelvisBritish Journal of Pharmacology, 2002