title: Altered calcium signalling in platelets from bile-duct-ligated rats.
abstract: 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.
authors.affiliation: Department of Physiology, Faculty of Medicine, University of Murcia, 30100 Murcia, Spain. ntma@um.es
authors.forename: Noemí M
authors.initials: NM
authors.lastname: Atucha
authors.forename: David
authors.initials: D
authors.lastname: Iyú
authors.forename: Antonia
authors.initials: A
authors.lastname: Alcaraz
authors.forename: Vladimir
authors.initials: V
authors.lastname: Rosa
authors.forename: Concepción
authors.initials: C
authors.lastname: Martínez-Prieto
authors.forename: M Clara
authors.initials: MC
authors.lastname: Ortiz
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Rosado
authors.forename: Joaquín
authors.initials: J
authors.lastname: García-Estañ
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D020013:Calcium Signaling; D004195:Disease Models, Animal; D006490:Hemostatics; D008105:Liver Cirrhosis, Biliary / Q000097:blood* / Q000209:etiology; D008297:Male; D015539:Platelet Activation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013917:Thrombin
chemical_list: D006490:Hemostatics; D013917:Thrombin; D002118:Calcium