V. I. Evlakhov, T. P. Berezina, T. V. Sergeev, M. V. Kuropatenko, I. Z. Poyassov
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引用次数: 0
Abstract
The β1,2-adrenergic receptor blocker
propranolol, β1-blocker bisoprolol, and central
presynaptic α2-adrenergic receptor agonist
methyldopa are used in clinical practice to treat the hyperadrenergic
type of postural orthostatic tachycardia syndrome. There are no
literature data on the effects of these drugs on vena cava flows
during postural tests. In acute experiments on anesthetized rabbits,
we studied blood flow changes in the cranial vena cava (CrVC) and
caudal vena cava (CdVC) during orthostatic (head-up tilt by 25°)
and antiorthostatic (head-down tilt by –25°) tests for 20 s after
propranolol, bisoprolol and methyldopa intravenous preadministration.
Before drug pretreatment, both CrVC and CdVC flows decreased in
response to orthostasis at the 4th and 20th s. During antiorthostasis,
CdVC flow increased at the 4th s and decreased to the baseline value
by the 20th s, while CrVC flow decreased by the 4th s and exceeded
the baseline level by the 20th s. After propranolol pretreatment,
CdVC flow decreased to a greater extent than in response to bisoprolol
and methyldopa pretreatment. After methyldopa pretreatment during
orthostasis, by the 20th s, CrVC flow decreased more notably than
CdVC flow, while after propranolol and bisoprolol pretreatment under
conditions of orthostasis, both CrVC and CdVC flows decreased about
equally. During antiorthostasis, 20 s after propranolol pretreatment,
CdVC flow increased more considerably compared to CrVC flow. After
bisoprolol and methyldopa pretreatment, CrVC flow increased in response
to antiorthostasis not only to a greater extent than CdVC flow but
even more pronouncedly compared to its initial increment. Thus,
postural tests after the pretreatment with the above drugs reveal
differences in the mechanisms of blood flow redistribution in CrVC
and CdVC basins.
期刊介绍：
Journal of Evolutionary Biochemistry and Physiology publishes original experimental and theoretical and review articles related to evolution of the main forms of metabolism in connection with life origin; comparative and ontogenetic physiology and biochemistry, biochemical evolution of animal world; as well as evolution of functions; morphology, pharmacology, pathophysiology and ecological physiology. The journal welcomes manuscripts from all countries in the English or Russian language.
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