title: Food restriction promotes downregulation of myocardial L-type Ca2+ channels.
abstract: Food restriction (FR) has been shown to impair myocardial performance. However, the mechanisms behind these changes in myocardial function due to FR remain unknown. Since myocardial L-type Ca2+ channels may contribute to the cardiac dysfunction, we examined the influence of FR on L-type Ca2+ channels. Male 60-day-old Wistar rats were fed a control or a restricted diet (daily intake reduced to 50% of the amount of food consumed by the control group) for 90 days. Myocardial performance was evaluated in isolated left ventricular papillary muscles. The function of myocardial L-type Ca2+ channels was determined by using a pharmacological Ca2+ channel blocker, and changes in the number of channels were evaluated by mRNA and protein expression. FR decreased final body weights, as well as weights of the left and right ventricles. The Ca2+ channel blocker diltiazem promoted a higher blockade on developed tension in FR groups than in controls. The protein content of L-type Ca2+ channels was significantly diminished in FR rats, whereas the mRNA expression was similar between groups. These results suggest that the myocardial dysfunction observed in previous studies with FR animals could be caused by downregulation of L-type Ca2+ channels.
authors.affiliation: Department of Clinical Cardiology, School of Medicine, UNESP - State University Júlio Mesquita Filho, Rubião Júnior, Botucatu, São Paulo, Brazil.
authors.forename: Loreta Casquel
authors.initials: LC
authors.lastname: De Tomasi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bruno
authors.forename: Mário Mateus
authors.initials: MM
authors.lastname: Sugizaki
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Lima-Leopoldo
authors.forename: André Ferreira
authors.initials: AF
authors.lastname: Nascimento
authors.forename: Silvio Assis de Oliveira
authors.initials: SA
authors.lastname: Júnior
authors.forename: Matheus Fécchio
authors.initials: MF
authors.lastname: Pinotti
authors.forename: Carlos Roberto
authors.initials: CR
authors.lastname: Padovani
authors.forename: André Soares
authors.initials: AS
authors.lastname: Leopoldo
authors.forename: Antonio Carlos
authors.initials: AC
authors.lastname: Cicogna
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000096:biosynthesis* / Q000502:physiology; D015536:Down-Regulation; D005508:Food Deprivation; D006352:Heart Ventricles / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D010210:Papillary Muscles / Q000187:drug effects / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D048348:Reverse Transcription
chemical_list: D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D012333:RNA, Messenger