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Modification of rat detrusor muscle contraction by ascorbic acid and citric acid involving enhanced neurotransmitter release and Ca 2+ influx
Author(s) -
Dasgupta Jaydip,
Elliott Ruth A.,
Tincello Douglas G.
Publication year - 2009
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.20701
Subject(s) - ascorbic acid , citric acid , carbachol , contraction (grammar) , calcium , endocrinology , medicine , chemistry , stimulation , biochemistry , food science
Aims Consumption of carbonated soft drinks is independently associated with the development of overactive bladder (OR 1.41, 95% Cl 1.02–1.95). We have shown previously that artificial sweeteners, present in carbonated soft drinks, enhanced detrusor muscle contraction. Other constituents of soft drinks are preservatives and antioxidants, we evaluated the effects of two of these, ascorbic acid and citric acid, on the contractile response of isolated rat bladder muscle strips. Methods Detrusor muscle strips were suspended in a perfusion organ bath. We determined the effect of ascorbic acid and citric acid on the contractile responses to electrical field stimulation (EFS) in the absence and presence of atropine, carbachol, α, β methylene ATP, potassium and calcium. Results Ascorbic acid and citric acid (10 −7 M to 10 −3 M) enhanced the contractile response to 10 Hz EFS compared to control (P < 0.01). The frequency and amplitude of spontaneous bladder contractions were enhanced in the presence of ascorbic acid and citric acid by 14%, 21%, 21%, and 11% respectively. Ascorbic acid 10 −4 M significantly increased the atropine resistant response to EFS 5 Hz by 37% (P < 0.01) and inhibited contraction in response to carbachol 10 −4 M by 24%, (P < 0.05). Both ascorbic acid 10 −4 M and citric acid 10 −5 M significantly enhanced maximum contractile responses to α, β methylene ATP, KCI and calcium compared to control. Conclusions Ascorbic acid and citric acid augmented bladder muscle contraction possibly by enhanced Ca 2+ influx. Presynaptic neurotransmitter release was enhanced by ascorbic acid. Carbonated beverages containing preservatives may aggravate symptoms of OAB. Neurourol. Urodyn. 28:542–548, 2009. © 2009 Wiley‐Liss, Inc.