Effects of stress on Kv1.5 K+ channel gene expression in the left ventricle of rat hearts.
Voltage-dependent K+ channels contribute to the repolarization phase of the cardiac action potential. An increase in Kv1.5 K+ channel gene expression by a pharmacological dose of glucocorticoid was reported recently in the heart of an adrenalectomized rat. In this study, we examined whether physiological elevations of glucocorticoid induced by tail suspension affects the K+ channel gene expression. Five-week-old male Wistar rats were subjected to tail suspension for three days. Total RNA was extracted from the ventricle, and the level of Kv1.5 mRNA was determined by Northern blot analysis. On the first day, the Kv1.5 mRNA had increased over the non-suspended rat. By the third day, mRNA had increased significantly by more than 3-fold. knowing that urinary excretions of glucocorticoid increase in tail-suspended rats, these findings suggest that physiologically elevated glucocorticoid may upregulate Kv1.5 K+ gene expression.
Nishiyama
A
A
Department of Circulation, Division of Regulation of Organ Function, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
Kambe
F
F
Kamiya
K
K
Kurokouchi
K
K
Kanda
K
K
Murata
Y
Y
Toyama
J
J
Seo
H
H
D000200:Action Potentials; D000818:Animals; D015870:Gene Expression / Q000502:physiology*; D005938:Glucocorticoids / Q000378:metabolism* / Q000502:physiology / Q000652:urine; D006352:Heart Ventricles / Q000378:metabolism; D019417:Hindlimb Suspension; D008297:Male; D015221:Potassium Channels / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger; D051381:Rats; D017208:Rats, Wistar; D013312:Stress, Physiological / Q000378:metabolism* / Q000652:urine; D013997:Time Factors; D016276:Ventricular Function
D005938:Glucocorticoids; D015221:Potassium Channels; D012333:RNA, Messenger