Food restriction promotes downregulation of myocardial L-type Ca2+ channels.
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.
De Tomasi
Loreta Casquel
LC
Department of Clinical Cardiology, School of Medicine, UNESP - State University Júlio Mesquita Filho, Rubião Júnior, Botucatu, São Paulo, Brazil.
Bruno
Alessandro
A
Sugizaki
Mário Mateus
MM
Lima-Leopoldo
Ana Paula
AP
Nascimento
André Ferreira
AF
Júnior
Silvio Assis de Oliveira
SA
Pinotti
Matheus Fécchio
MF
Padovani
Carlos Roberto
CR
Leopoldo
André Soares
AS
Cicogna
Antonio Carlos
AC
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
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D012333:RNA, Messenger