{"title":"Effects of Cold on Adrenoreactivity of the Rat Superior Mesenteric Artery","authors":"V. N. Yartsev","doi":"10.1134/s0022093024020200","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The effect of cold on the reactivity of the rat superior mesenteric\nartery (SMA), estimated by the magnitude of contractile responses\nof its segments to noradrenaline (NA, 0.01–10.0 µM) and electrical field\nstimulation (EFS) of the perivascular nerves at a frequency of 3,\n10 and 40 Hz in both the absence and presence of NA in the medium\nat a temperature of 37 or 25°C, was studied in isometric experiments. Cooling\ndid not alter SMA tone evoked by NA at all its concentrations used.\nIn both the absence and presence of low NA concentrations (0.01–0.10\nµM), cooling led to a significant decrease in the neurogenic SMA\nresponse at all EFS frequencies, while in the presence of NA at\na high concentration (1–10 µM), cooling had no significant effect\non this response. In the presence of NA at a low concentration,\ncooling insignificantly (at low EFS frequencies) and significantly\n(at high EFS frequencies) reduced the potentiating effect of NA\non the neurogenic SMA constriction. At a high concentration under\nnormal temperature conditions (37°C), NA reduced the neurogenic\nSMA constriction at all EFS frequencies, while under cooling conditions\n(25°C), it had a potentiating effect at low and a depressing effect\nat high EFS frequencies. These results demonstrate that the depressing\neffect of cold on the neurogenic constriction of the rat SMA, occurring\nat low and disappearing at high NA concentrations, as well as on\nthe NA-evoked potentiation of the neurogenic vasoconstriction, is irrelevant\nto a decrease in the contractile effect of NA, which is the main\nneurotransmitter in this artery. These effects may contribute to\nblood rerouting from the surface to the deeper regions of the body,\nthus reducing heat loss and improving thermoregulation.</p>","PeriodicalId":15805,"journal":{"name":"Journal of Evolutionary Biochemistry and Physiology","volume":"101 1","pages":""},"PeriodicalIF":0.6000,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Evolutionary Biochemistry and Physiology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1134/s0022093024020200","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The effect of cold on the reactivity of the rat superior mesenteric
artery (SMA), estimated by the magnitude of contractile responses
of its segments to noradrenaline (NA, 0.01–10.0 µM) and electrical field
stimulation (EFS) of the perivascular nerves at a frequency of 3,
10 and 40 Hz in both the absence and presence of NA in the medium
at a temperature of 37 or 25°C, was studied in isometric experiments. Cooling
did not alter SMA tone evoked by NA at all its concentrations used.
In both the absence and presence of low NA concentrations (0.01–0.10
µM), cooling led to a significant decrease in the neurogenic SMA
response at all EFS frequencies, while in the presence of NA at
a high concentration (1–10 µM), cooling had no significant effect
on this response. In the presence of NA at a low concentration,
cooling insignificantly (at low EFS frequencies) and significantly
(at high EFS frequencies) reduced the potentiating effect of NA
on the neurogenic SMA constriction. At a high concentration under
normal temperature conditions (37°C), NA reduced the neurogenic
SMA constriction at all EFS frequencies, while under cooling conditions
(25°C), it had a potentiating effect at low and a depressing effect
at high EFS frequencies. These results demonstrate that the depressing
effect of cold on the neurogenic constriction of the rat SMA, occurring
at low and disappearing at high NA concentrations, as well as on
the NA-evoked potentiation of the neurogenic vasoconstriction, is irrelevant
to a decrease in the contractile effect of NA, which is the main
neurotransmitter in this artery. These effects may contribute to
blood rerouting from the surface to the deeper regions of the body,
thus reducing heat loss and improving thermoregulation.
摘要 在等长实验中研究了冷对大鼠肠系膜上动脉（SMA）反应性的影响，该影响是通过其节段对去甲肾上腺素（NA，0.01-10.0µM）的收缩反应大小以及在37或25°C的介质中无NA和有NA时血管周围神经对频率为3、10和40 Hz的电场刺激（EFS）的反应大小来估计的。在没有NA和有低浓度NA（0.01-0.10µM）的情况下，冷却会导致神经源性SMA在所有EFS频率下的反应显著下降，而在有高浓度NA（1-10µM）的情况下，冷却对这种反应没有显著影响。在低浓度 NA 存在的情况下，冷却对神经源性 SMA 收缩的增效作用（低 EFS 频率时）不明显，而（高 EFS 频率时）则明显减弱。在正常温度条件下（37°C），高浓度NA可降低所有EFS频率下的神经源性SMA收缩，而在冷却条件下（25°C），低浓度NA对低EFS频率有促进作用，对高EFS频率有抑制作用。这些结果表明，寒冷对大鼠 SMA 神经源性收缩的抑制作用（在 NA 浓度较低时出现，在 NA 浓度较高时消失）以及 NA 引起的神经源性血管收缩的增效作用与 NA 收缩效应的降低无关，而 NA 是该动脉的主要神经递质。这些效应可能有助于血液从体表重新流向身体深层区域，从而减少热量流失并改善体温调节。
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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