Cardiovascular effects of urotensin II in different brain areas.
It has been shown that intracerebroventricular injection of urotensin II (UII)-induced hypotensive and bradycardiac responses. Here, we tested the cardiovascular roles of UII in different brain areas by microinjection of UII into the A1 and A2 areas (noradrenergic cells found in the lower part of the medulla that have been designated either A1 or A2 areas), the paraventricular and the arcuate nucleus. In urethane-anaesthetized rats, we observed that: (1) microinjection of UII into the A1 area induced dose-related depressor and bradycardiac responses; (2) mean arterial blood pressure (mABP) and heart rate (HR) did not change significantly after microinjection of UII into the A2 area; and (3) significant increases in mABP and HR were induced after microinjection of 10 pmol UII into either the paraventricular or arcuate nucleus. The above results suggest that UII, in different brain areas, plays different roles in cardiovascular regulation and the A1 area is a very important action site for UII in cardiovascular regulation.
Lu
Yang
Y
Department of Physiology, Health Science Center, Peking University, Beijing, PR China.
Zou
Chang-Jiang
CJ
Huang
Da-Wei
DW
Tang
Chao-Shu
CS
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002319:Cardiovascular System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014579:Urotensins / Q000494:pharmacology*
D014579:Urotensins; C029677:urotensin II