AJP - Heart and Circulatory Physiology, Vol 232, Issue 2 140-H145, Copyright © 1977 by American Physiological Society
Norepinephrine release in isolated arteries induced by K-free solution
A. Bonaccorsi, K. Hermsmeyer, C. B. Smith and D. F. Bohr
Helical strips from arteries with a rich sympathetic innervation (rat tail
and femoral, and dog mesenteric arteries) develop a sustained contracture
when exposed to a K-free physiological salt solution (PSS). The contracture
can be blocked by phentolamine and does not occur in arteries whose nerve
terminals have been destroyed with 6-hydroxydopamine. The temporal
relationship between force development and efflux of NE was determined.
Helical strips of rat tail arteries or dog mesenteric arteries were
incubated in PSS containing 1-norepinephrine-7-3H([3H]NE). They were then
transferred to a superfusion system which allowed isometric recordings and
collection of the superfusate for the estimation of [3H]NE content.
Following exposure to a K-free PSS force development paralleled NE release
and both parameters were potentiated by ouabain. These data demonstrate
that this neurogenic mechanism plays a most important role in the K-free
contracture of the vascular smooth muscle studied. It is in accord with the
observation that NE is released by adrenergic nerves following inhibition
of Na+-K+-ATPase.
