Distribution of atrial natriuretic peptide and its effects on contraction and intracellular calcium in ventricular myocytes from streptozotocin-induced diabetic rat.
The distribution of atrial natriuretic peptide (ANP) in blood plasma and cardiac muscle and its effects on ventricular myocyte contraction and intracellular free calcium concentration [Ca2+]i in the streptozotocin (STZ)-induced diabetic rat have been investigated. Blood plasma concentration and heart atrial and ventricular contents of ANP were significantly increased in STZ-treated rats compared to age-matched controls. STZ treatment increased the number of ventricular myocytes immunolabeled with antibodies against ANP. In control myocytes the percentage of cells that labeled positively and negatively were 17% versus 83%, respectively. However, in myocytes from STZ-treated rat the percentages were 52% versus 53%. Time to peak (TPK) shortening was significantly and characteristically prolonged in myocytes from STZ-treated rats (360+/-5 ms) compared to controls (305+/-5 ms). Amplitude of the Ca2+ transient was significantly increased in myocytes from STZ-treated rats compared to controls (0.39+/-0.02 versus 0.29+/-0.02 fura-2 RU in controls) and treatment with ANP reduced the amplitude of the Ca2+ transient to control levels. ANP may have a protective role in STZ-induced diabetic rat heart.
Howarth
F C
FC
Department of Physiology, Faculty of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, UAE. chris.howarth@uaeu.ac.ae
Adem
A
A
Adeghate
E A
EA
Al Ali
N A
NA
Al Bastaki
A M
AM
Sorour
F R
FR
Hammoudi
R O
RO
Ghaleb
N A
NA
Chandler
N J
NJ
Dobrzynski
H
H
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood / Q000494:pharmacology* / Q000502:physiology*; D003921:Diabetes Mellitus, Experimental / Q000473:pathology / Q000503:physiopathology*; D006352:Heart Ventricles / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D032342:Muscle Cells / Q000187:drug effects / Q000502:physiology*; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin / Q000633:toxicity
D013311:Streptozocin; D009320:Atrial Natriuretic Factor