title: Slow/cardiac sarcoplasmic reticulum Ca2+-ATPase and phospholamban mRNAs are expressed in chronically stimulated rabbit fast-twitch muscle.
abstract: Fast-twitch extensor digitorum longus muscles of the rabbit were subjected to chronic low-frequency stimulation during different time periods. Changes in the relative amounts of mRNAs encoding fast and slow/cardiac Ca2+-ATPase isoforms were assessed through the use of an RNase-protection assay. Stimulation-induced increases in slow cardiac Ca2+-ATPase and phospholamban mRNAs were quantified by mRNA hybridization. Prolonged stimulation resulted in an exchange of the fast with the slow/cardiac Ca2+-ATPase isoform mRNAs. The exchange was complete after 72 d of stimulation as compared with normal slow-twitch soleus muscle. The tissue content of phospholamban mRNA reached levels similar to that found in normal slow-twitch soleus muscle by the same time. The conversion of the sarcoplasmic reticulum coincided with the fast-to-slow troponin C isoform transition, previously investigated in the same muscles.
authors.affiliation: Banting and Best Department of Medical Research, Charles H. Best Institute, University of Toronto.
authors.forename: E
authors.initials: E
authors.lastname: Leberer
authors.forename: K T
authors.initials: KT
authors.lastname: Härtner
authors.forename: C J
authors.initials: CJ
authors.lastname: Brandl
authors.forename: J
authors.initials: J
authors.lastname: Fujii
authors.forename: M
authors.initials: M
authors.lastname: Tada
authors.forename: D H
authors.initials: DH
authors.lastname: MacLennan
authors.forename: D
authors.initials: D
authors.lastname: Pette
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics*; D000252:Calcium-Transporting ATPases / Q000235:genetics*; D004558:Electric Stimulation; D015870:Gene Expression; D008297:Male; D009132:Muscles / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D000099211:Phospholamban
chemical_list: D002135:Calcium-Binding Proteins; D000252:Calcium-Transporting ATPases; D012333:RNA, Messenger; D000099211:Phospholamban