[Adrenergic receptor and knockout mouse: 1) Beta adrenergic receptor knockout mouse].
Functional analysis of beta 1 and beta 2 adrenergic receptor (AR) subtypes has been made possible by establishing knockout mice (KO) with abolished beta 1 and/or beta 2 AR expression. Neither resting heart rate nor resting blood pressure of beta 1 AR KO, beta 2 AR KO, or beta 1/beta 2 KO differed significantly from those of wild-type mice. The chronotropic response to isoproterenol was significantly attenuated in beta 1 AR KO and beta 1/beta 2 KO, whereas there was no detrimental effect on heart rate in beta 2 AR KO. This suggests that chronotropy is mediated by beta 1 AR. In terms of the vasodilatory response to isoproterenol, there appears to be a graded and additive attenuation of the hypotensive response in beta 1 AR KO, beta 2 AR KO, and beta 1/beta 2 KO. Vascular relaxation is thought to be controlled by both beta 1 AR and beta 2 AR. Tachycardia induced by exercise was significantly attenuated in beta 1 AR KO, and beta 1/beta 2 KO. beta 2 AR KO subjected to treadmill exercise showed significant hypertension, increased oxygen consumption, and ability of long distance running.
Mizobe
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Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kyoto 602-8566.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D007545:Isoproterenol / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D010805:Physical Conditioning, Animal / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D018342:Receptors, Adrenergic, beta-1 / Q000502:physiology*; D018343:Receptors, Adrenergic, beta-2 / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology
D000318:Adrenergic beta-Agonists; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2; D007545:Isoproterenol