The effects of reactive oxygen species on calcium- and carbachol- induced contractile responses in β-escin permeabilized rat bladder

• Published in: Naunyn-Schmiedeberg's archives of pharmacology 2008-12, Vol.378 (6), p.645-653
• Main Authors: Durlu-Kandilci, N. Tugba, Sahin-Erdemli, Inci
• Format: Article
• Language: English
• Subjects: Animals; Biomedical and Life Sciences; Biomedicine; Calcium - metabolism; Calcium-Transporting ATPases - antagonists & inhibitors; Calcium-Transporting ATPases - physiology; Carbachol - pharmacology; Contractile Proteins - physiology; Escin - pharmacology; In Vitro Techniques; Indoles - pharmacology; Inositol 1,4,5-Trisphosphate Receptors - physiology; Male; Mitochondrial Proteins - physiology; Muscle Contraction - drug effects; Muscle Contraction - physiology; Muscle, Smooth - drug effects; Muscle, Smooth - physiology; Neurosciences; Original Article; Permeability; Pharmacology/Toxicology; Rats; Rats, Wistar; Reactive Oxygen Species - metabolism; Sarcoplasmic Reticulum - drug effects; Sarcoplasmic Reticulum - metabolism; Urinary Bladder - drug effects; Urinary Bladder - physiology
• ISSN: 0028-1298; 1432-1912
• DOI: 10.1007/s00210-008-0326-3

The effect of reactive oxygen species on contractions in β-escin permeabilized rat detrusor was investigated. Cumulative calcium contractions were inhibited by hydrogen peroxide (H 2 O 2 ) and hydroxyl (•OH) but not by superoxide (O 2 ¯•). The sarcoplasmic reticulum calcium-ATPase inhibitor cyclopiazonic acid (CPA) and the mitochondrial blocker carbonyl cyanide p-trifluromethoxyphenylhydrazone (FCCP) decreased the calcium contractions, however in their presence, H 2 O 2 and •OH did not have further effect. Carbachol contractions were inhibited by either H 2 O 2 /•OH/O 2 ¯• or CPA/FCCP. In the presence of CPA, carbachol contractions were not affected by H 2 O 2 and •OH but further decreased by O 2 ¯•. On the other hand, only H 2 O 2 and •OH elicited additional inhibition in carbachol responses in the presence of FCCP. Inositol triphosphate contraction was inhibited by •OH whereas none of the radicals affect carbachol induced calcium sensitization. These results show that H 2 O 2 and •OH affects sarcoplasmic reticulum where O 2 ¯• acts on mitochondria to change contractions in rat detrusor smooth muscle.