AJP - Regulatory, Integrative and Comparative Physiology, Vol 249, Issue 1 85-R90, Copyright © 1985 by American Physiological Society
Corticotropin-releasing factor, sauvagine, and urotensin I: effects on blood flow
H. J. Lenz, L. A. Fisher, W. W. Vale and M. R. Brown
Corticotropin-releasing factor (CRF), sauvagine (SVG), and urotensin I (UI)
were tested for their effects on superior mesenteric blood flow in
conscious dogs. Intravenous (iv) administration of CRF, SVG, and UI induced
an immediate rise of mesenteric blood flow that was associated with a
decrease in mean arterial pressure and an increase in heart rate.
Intracerebroventricular (ICV) injection of SVG and UI, but not CRF, rapidly
(within 5 min after injection) elicited a long (90 min) elevation of
mesenteric blood flow. Central administration of these peptides induced a
delayed rise in heart rate and slightly elevated mean arterial pressure.
The finding that CRF given ICV did not increase mesenteric blood flow could
not be explained by the release of vasoactive agents such as vasopressin,
epinephrine, or norepinephrine. After injection of CRF, SVG, and UI, plasma
concentrations of CRF-, SVG-, and UI-like immunoreactivity did not increase
as determined by radioimmunoassay. These results indicate that SVG and UI,
but not CRF, administered ICV produce a long increase of mesenteric blood
flow in conscious dogs. Because iv SVG and UI decrease mean arterial
pressure and ICV SVG and UI increase mean arterial pressure and do not
cause an increase in SVG- and UI-like immunoreactivity in the peripheral
circulation, it is proposed that SVG and UI injected into the third
cerebral ventricle act within the central nervous system to increase
superior mesenteric blood flow in the dog.
