The inhibitory effect of the flavonoid galangin on urinary bladder smooth muscle contractility is mediated in part by modulation of Ca2+ release from intracellular stores.
The present study was designed to examine the effect of the flavonoid galangin on the muscarinic receptor mediating a carbachol-induced contraction and to investigate the effect of the flavonoid on Ca (2+) release from intracellular stores in the urinary bladder of the pig. Galangin (10(-7) -10(-4)M) produced a concentration-dependent inhibition of the contractile responses to electrical field stimulation (EFS) and carbachol (10(-5)M). Galangin (3 x 10(-5)M) reduced muscle contractions evoked by carbachol (10(-5)M) in calcium-containing solution as well as contractions evoked by carbachol and caffeine (2 x 10(-2)M) in Ca(2+)-free solutions significantly. The flavonoid had a stronger effect on the maximal force of the contractions induced by caffeine, compared to contractions induced by carbachol. These results suggest that galangin has an important effect on the intracellular calcium mobilization, which might be attributed predominantly to its influence on ryanodine-receptors.
Dambros
Miriam
M
Department of Urology, University of Maastricht, P. Debyelaan 25, Postbus 5800, 6202 AZ Maastricht, The Netherlands. miriamdambros@yahoo.com.br
van Deutekom
Marjanka
M
de Jongh
Rik
R
van Koeveringe
Gommert A
GA
De Mey
Jo G
JG
van Kerrebroeck
Philip
P
D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D018678:Cholinergic Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D013552:Swine; D001743:Urinary Bladder / Q000187:drug effects
D018678:Cholinergic Agents; D005419:Flavonoids; D010936:Plant Extracts; C037032:galangin