Cross-talk between the sarcoplasmic reticulum and the mitochondrial calcium handling systems may play an important role in the regulation of contraction in anococcygeus smooth muscle.
Mitochondrial Ca(2+) and its relation with the contraction induced by phenylephrine was investigated. In normal Ca(2+), carbonyl cyanide p-(trifluoro-methoxy)phenyl-hydrazone (FCCP) and oligomycin produced contraction similar to that promoted by phenylephrine. Phenylephrine-induced contraction was reduced by FCCP+oligomycin. In Ca(2+)-free, FCCP+oligomycin did not induce contraction. Response to FCCP+oligomycin was reduced upon Ca(2+) repletion and this response was lower than that to phenylephrine. Ca(2+) concentration was increased by FCCP+oligomycin. Since a profuse net of sarcoplasmic reticulum encloses mitochondria, a cross-talk between the two organelles may play an important role in the phenylephrine-induced contraction in presence of Ca(2+) encountered in both sarcoplasmic reticulum and extracellular medium of anococcygeus cells.
Restini
Carolina A
CA
Laboratório de Farmacologia, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de Sao Paulo, Av. Do Café s/no., 14040-903 Ribeirão Preto, SP, Brazil.
Moreira
Jorge E
JE
Bendhack
Lusiane M
LM
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology*; D004338:Drug Combinations; D016257:Fura-2 / Q000031:analogs & derivatives / Q000378:metabolism; D007552:Isotonic Solutions; D008297:Male; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009840:Oligomycins / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D014475:Uncoupling Agents / Q000494:pharmacology
D004338:Drug Combinations; D007552:Isotonic Solutions; D009840:Oligomycins; D014475:Uncoupling Agents; D010656:Phenylephrine; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D002110:Caffeine; D011188:Potassium; D002118:Calcium; D016257:Fura-2