title: Adrenomedullin 2 microinjection into the nucleus tractus solitarius elevates arterial pressure and heart rate in rats.
abstract: Adrenomedullin 2 (AM2), a novel member of the calcitonin gene-related peptide family, has emerged as a multifunctional peptide controlling endocrine and cardiovascular functions and physiological behaviors. Both central and peripheral administration of AM2 can have profound effects on systemic and/or pulmonary circulation in mammals. However, the target nuclei of AM2 and the role of central AM2 in cardiovascular regulation remain unknown. In the present study, we microinjected AM2 into the rat nucleus tractus solitarius (NTS), the central termination site of baroreceptor afferents. Consistent with previous reports showing the hypertensive effect of intracerebroventricular administration of AM2, the direct microinjection of the peptide into the NTS increased arterial pressure as well as heart rate in rats. Importantly, this effect of AM2 on cardiovascular regulation was significantly attenuated by an antagonist of receptor components for AM2 that were abundant in the rat NTS. Our results indicate that AM2 may play an important role in the regulation of the cardiovascular system at the NTS level.
authors.affiliation: Department of Physiology, Wakayama Medical University School of Medicine, 811-1 Kimiidera, Wakayama City, Wakayama 641-8509, Japan.
authors.forename: He
authors.initials: H
authors.lastname: Cui
authors.forename: Akira
authors.initials: A
authors.lastname: Kohsaka
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Waki
authors.forename: Sabine
authors.initials: S
authors.lastname: Gouraud
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakamura
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yukawa
authors.forename: Atsutoshi
authors.initials: A
authors.lastname: Hatada
authors.forename: Mohammad Eliusur Rahman
authors.initials: ME
authors.lastname: Bhuiyan
authors.forename: Masanobu
authors.initials: M
authors.lastname: Maeda