PMID: 23603931Apr 23, 2013Paper

Angiotensin AT(1)-receptor blockers enhance cardiac responses to parasympathetic nerve stimulation via presynaptic AT(1) receptors in pithed rats

Journal of Pharmacological Sciences
Fumiko YamakiYoshinobu Takata

Abstract

In the present study, we investigated the effects of angiotensin AT1-receptor blockers, KT3-671 and losartan, on the cardiac vagal neurotransmission in pithed rats. The bradycardia induced by vagal nerve stimulation (VNS, at 5 Hz) was potentiated significantly and dose-dependently by KT3-671 and also losartan. This enhancement effect of KT3-671 (10 mg/kg) was slightly potent than that of losartan (10 mg/kg). On the other hand, an angiotensin AT2-receptor blocker, PD123319 (10 mg/kg), did not affect VNS-induced bradycardia. KT3-671 and losartan did not affect the exogenous acetylcholine-evoked bradycardia. Intravenous infusion of AngII (100 ng/kg per min) attenuated the VNS-induced bradycardia. This inhibitory effect of AngII on bradycardia was restored by both KT3-671 and losartan. These results suggest that endogenous AngII can have a tonic inhibitory effect on cardiac vagal transmission by stimulating the presynaptic AT1 receptors not AT2 receptors. Suppression of this mechanism by the AT1-receptor blockers causes the facilitation of acetylcholine release from vagal nerve endings. This acceleratory effect of AT1-receptor blockers on cardiac vagal neurotransmission may contribute to the lack of reflex tachycardia following hyp...Continue Reading

References

Nov 1, 1978·Clinical Science and Molecular Medicine·R J CodyF M Fouad
Sep 1, 1985·British Journal of Clinical Pharmacology·J F GiudicelliD Jacolot
Jan 1, 1982·Clinical and Experimental Hypertension. Part A, Theory and Practice·H GavrasR O Davies
Jan 1, 1982·British Journal of Pharmacology·E K Potter
Jan 1, 1995·Journal of Cardiovascular Pharmacology·S MochizukiA Tomiyama
Sep 1, 1993·British Journal of Pharmacology·M Rechtman, H Majewski
Jan 13, 2004·Journal of Cardiovascular Pharmacology·Malek El MuayedLars Christian Rump
Jul 24, 2004·Journal of Pharmacological Sciences·Yoshinobu TakataHitoshi Kato
Jul 24, 2007·American Journal of Physiology. Heart and Circulatory Physiology·Toru KawadaMasaru Sugimachi

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Citations

Mar 14, 2019·The Cochrane Database of Systematic Reviews·Roos M SmitsMarian G Showell
May 8, 2019·Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan·Fumiko YamakiYoshio Tanaka
May 8, 2015·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Jean C HardwickJeffrey L Ardell

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