Jrh. Mauban et al., Adrenergic stimulation of rat resistance arteries affects Ca2+ sparks, Ca2+ waves, and Ca2+ oscillations, AM J P-HEAR, 280(5), 2001, pp. H2399-H2405
Citations number
33
Categorie Soggetti
Cardiovascular & Hematology Research
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
Confocal laser scanning microscopy and fluo 4 were used to visualize local
and whole cell Ca2+ transients within individual smooth muscle cells (SMC)
of intact, pressurized rat mesenteric small arteries during activation of a
lpha (1)-adrenoceptors. A method was developed to record the Ca2+ transient
s within individual SMC during the changes in arterial diameter. Three dist
inct types of "Ca2+ signals" were influenced by adrenergic activation (agon
ist: phenylephrine). First, asynchronous Ca2+ transients were elicited by l
ow levels of adrenergic stimulation. These propagated from a point of origi
n and then filled the cell. Second, synchronous, spatially uniform Ca2+ tra
nsients, not reported previously, occurred at higher levels of adrenergic s
timulation and continued for long periods during oscillatory vasomotion. Fi
nally, Ca2+ sparks slowly decreased in frequency of occurrence during expos
ure to adrenergic agonists. Thus adrenergic activation causes a decrease in
the frequency of Ca2+ sparks and an increase in the frequency of asynchron
ous wavelike Ca2+ transients, both of which should tend to decrease arteria
l diameter. Oscillatory vasomotion is associated with spatially uniform syn
chronous oscillations of cellular [Ca2+] and may have a different mechanism
than the asynchronous, propagating Ca2+ transients.