Microinjection of urocortin into the rat nucleus tractus solitarii decreases arterial blood pressure.
Systemic administration of urocortin I (Ucn I), a member of the corticotrophin-releasing factor (CRF) peptide family, modulates cardiovascular system. In the central nervous system, Ucn I is found in the nucleus tractus solitarii (NTS), which plays an important role in regulating arterial blood pressure (ABP) and heart rate (HR) in response to activation of the baroreceptor afferents. In this study, we examined the effects of Ucn I, which has a high affinity for both type 1 and type 2 CRF receptors (i.e. CRF-R1 and -R2), on cardiovascular functions at the level of the NTS. A specific agonist of CRF-R1 (i.e. CRF) and a specific agonist of CRF-R2 (i.e. Urocortin II) were also tested to identify the specific cardiovascular effects induced by individual activation of either CRF-R1 or -R2. We found that Ucn I microinjected into the rat NTS produced a significant reduction in both ABP and HR. Both agonists for CRF-R1 and -R2 microinjected into the NTS also reduced ABP and HR. Our results suggest that Ucn I in the NTS may play an important role in cardiovascular regulation and the cardiovascular effects of Ucn I may be mediated by activation of both CRF-R1 and -R2, which are known to be present in the NTS.
Yamazaki
Toshiya
T
Department of Physiology, Wakayama Medical University School of Medicine, 811-1 Kimiidera, Wakayama City 641-8509, Japan. wokey@wakayama-med.ac.jp
Waki
Hidefumi
H
Kohsaka
Akira
A
Nakamura
Takeshi
T
Cui
He
H
Yukawa
Kazunori
K
Maeda
Masanobu
M
D000818:Animals; D001158:Arteries / Q000294:innervation* / Q000502:physiology; D001341:Autonomic Nervous System / Q000187:drug effects / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D008297:Male; D008845:Microinjections; D011311:Pressoreceptors / Q000187:drug effects / Q000502:physiology; D051381:Rats; D018019:Receptors, Corticotropin-Releasing Hormone / Q000819:agonists / Q000378:metabolism; D017552:Solitary Nucleus / Q000187:drug effects / Q000378:metabolism*; D054832:Urocortins / Q000378:metabolism* / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D017833:Visceral Afferents / Q000187:drug effects / Q000502:physiology; D000099052:CRF Receptor, Type 1
C101531:CRF receptor type 2; D018019:Receptors, Corticotropin-Releasing Hormone; D054832:Urocortins; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone