Ca2+ regulation in detrusor smooth muscle from developing fetal sheep bladders.
Wu, C, Sui, G, Thiruchelvam, N, Cuckow, P and Fry, CH (2006) Ca2+ regulation in detrusor smooth muscle from developing fetal sheep bladders. Cell Calcium, 39 (4). 367 - 374. ISSN 0143-4160
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Sheep fetus is a useful model to study in utero bladder outflow obstruction but little is known about cell physiology of fetal bladders. To remedy this defect we have characterised intracellular Ca(2+) regulation in fetal sheep myocytes of different developmental ages. Fetal detrusor myocytes had a similar resting [Ca(2+)](i) to adult cells and exhibited transient [Ca(2+)](i) increases in response to carbachol, ATP, high-K, caffeine and low-Na. The carbachol transients were abolished by atropine and caffeine; the ATP response was blocked by alpha,beta-methylene ATP; high-K-evoked [Ca(2+)](i) rises were antagonised by verapamil. The maximal responses to carbachol, high-K, caffeine and low-Na in fetal cells were similar to those of adult counterparts, whilst the ATP response was smaller (p < 0.05). These variables were largely similar between the three gestational groups with the exception of ATP-induced response between early fetal and adult bladders (p < 0.05). Dose-response curves to carbachol demonstrated an increase of potency between mid-gestation and early adulthood (p < 0.05). These data show that muscarinic receptors coupled to intracellular Ca(2+) release, P2X receptor-linked Ca(2+) entry, depolarisation-induced Ca(2+) rise via L-type Ca(2+) channels, Na(+)/Ca(2+) exchange and functional intracellular Ca(2+) stores are all operational in fetal bladder myocytes. Whilst most of Ca(2+) regulators are substantially developed and occur at an early fetal age, a further functional maturation for cholinergic sensitivity and purinergic efficacy continues throughout to adulthood.
|Additional Information:||NOTICE: this is the author’s version of a work that was accepted for publication in Cell Calcium. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Cell Calcium, 39(4), April 2006, DOI 10.1016/j.ceca.2006.01.002.|
|Uncontrolled Keywords:||Adenosine Triphosphate, Animals, Caffeine, Calcium, Calcium Channel Agonists, Calcium Channels, Carbachol, Cell Membrane Permeability, Cholinergic Agonists, Dose-Response Relationship, Drug, Gene Expression Regulation, Muscle Cells, Muscle, Smooth, Sheep, Urinary Bladder|
|Divisions:||Faculty of Health and Medical Sciences > Clinical Medicine|
|Depositing User:||Symplectic Elements|
|Date Deposited:||23 Mar 2012 12:42|
|Last Modified:||23 Sep 2013 19:20|
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