The effects of dietary potassium depletion on the ultrastructure of cardiac ventricular myocytes in rabbits: a morphometric study.
The ultrastructure of cardiac ventricular myocytes isolated from normal and chronically K-depleted rabbits was analysed using morphometric techniques. Myocytes from normal animals showed a quantitatively similar distribution of organelle volumes to those previously reported for isolated myocytes from rat, and for whole myocardium in a variety of species. Myocytes from animals that had been fed a K-deficient diet for 25 days had a significantly increased surface density of junctional sarcoplasmic reticulum with the T-tubules and a significant increase in the surface density of the T-system itself. There were no other differences. The increase in junctional SR and T-system may be related to the defect in cardiac contractility that has been reported for rabbit following K depletion, and may represent an adaptive mechanism acting to protect the heart against Ca overload.
Skepper
J N
JN
Department of Anatomy, Cambridge, UK.
Warley
A
A
Ward
J P
JP
D000818:Animals; D008297:Male; D008854:Microscopy, Electron; D008929:Mitochondria, Heart / Q000648:ultrastructure; D009206:Myocardium / Q000166:cytology / Q000648:ultrastructure*; D009210:Myofibrils / Q000648:ultrastructure; D015388:Organelles / Q000648:ultrastructure; D011191:Potassium Deficiency / Q000473:pathology*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000648:ultrastructure