Enhancement of norepinephrine-induced transient contraction in aortic smooth muscle of diabetic mice.
Changes in norepinephrine-induced transient contractions in Ca2+-deficient solution were investigated in the aortic smooth muscles of diabetic ALS (alloxan-induced diabetes susceptible) mice. The transient contractions in diabetic mice were significantly larger than those in normal mice. The longer incubation of the muscle preparations in Ca2+-deficient solution made the transient contractions smaller, probably due to the leakage and decrease in norepinephrine-releasable stored Ca2+. The rate of this reduction in contraction was slower in diabetic mice. These results suggest that the leakage of intracellular stored Ca2+ caused by extracellular Ca2+ deficiency is attenuated in diabetic mice, contributing to enhanced norepinephrine-induced transient contractions.
Abe
Asaki
A
Department of Animal Science, Faculty of Agriculture, Okayama University, Okayama 700 8530, Japan. abeasaki@cc.okayama-u.ac.jp
Kawasoe
Chiaki
C
Kondo
Yasuhiro
Y
Sato
Katsunori
K
D000818:Animals; D001011:Aorta / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology*
D009638:Norepinephrine