Liver Cirrhosis Research Today is a free monthly online journal that collates and summarizes the latest research about Liver Cirrhosis, including details on alcohol, treatment, drugs, effects, causes. | ||||||||
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Altered calcium signalling in platelets from bile-duct-ligated rats.Atucha NM, Iyú D, Alcaraz A, Rosa V, Martínez-Prieto C, Ortiz MC, Rosado JA, García-Estañ J Department of Physiology, Faculty of Medicine, University of Murcia, 30100 Murcia, Spain. ntma@um.es In the present study, we have analysed the mechanisms of Ca(2+) entry and release in platelets obtained from BDL (bile-duct-ligated) rats, 11-13 days and 4 weeks after surgery. Platelets were washed and loaded with fura-2, and [Ca(2+)](i) (cytosolic Ca(2+) concentration) was determined in cell suspensions by means of fluorescence spectroscopy. Basal [Ca(2+)](i) was similar in platelets from BDL rats compared with those from their respective controls, both in the absence and presence of extracellular Ca(2+). Platelet stimulation with thrombin in the absence and presence of extracellular Ca(2+) induced a rapid rise in [Ca(2+)](i) that was of greater magnitude in platelets from BDL rats than in controls. Ca(2+) storage was significantly elevated in platelets from BDL rats, as well as the activity of SERCA (sarcoplasmic/endoplasmic-reticulum Ca(2+)-ATPase). Capacitative Ca(2+) entry, as evaluated by inhibition of SERCA with thapsigargin, was also altered in platelets from BDL rats, having lower rates of Ca(2+) entry. In conclusion, chronic BDL alters intracellular Ca(2+) homoeostasis in platelets, such that an enhanced Ca(2+) release is evoked by thrombin, which may be due to an increased amount of Ca(2+) stored in the intracellular organelles and secondary to an enhanced activity of SERCA. These alterations are already evident before cirrhosis has completely developed and occurs during the cholestasis phase. Published 3 January 2007 in Clin Sci (Lond), 112(3): 167-74.
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