Changes in tension of spiral strips from canine and human veins induced by various drugs are compared with results from the literature on human veins. The order of potencies of alpha-adrenoceptor stimulating amines (adrenaline greater than noradrenaline greater than dopamine greater than isoprenaline) is similar in human and canine veins. Comparison of the affinities for alpha-adrenoceptors of pharmacologic drugs (thymoxamine, indoramine, clonidine, dihydroergotamine) suggest marked differences between the alpha-adrenoceptors in veins from man and dog. Venoconstriction mediating 5-HT receptors and a very small population of beta-adrenoceptors exist in both species. Human veins are always dilated by histamine, while canine femoral veins in vitro are relaxed by lower and contracted by higher histamine concentrations. Prostaglandin F2 alpha constricts both canine femoral and human hand veins. PGA2 and PGE2 increase the tension of canine and human veins in vitro but dilate human hand veins in situ. The order of potencies of ergot alkaloids in canine femoral veins is ergotamine greater than dihydroergovaline greater than dihydroergotamine = dihydroergostine greater than methysergide, whereas in human hand veins it is ergotamine = dihydroergovaline greater than methysergide greater than dihydroergotamine greater than dihydroergostine. In dogs the venoconstrictor effect of ergotamine is mediated by at least 3 mechanisms: stimulation of [1] alpha-adrenoceptors, [2] 5-HT receptors and [3] endogenous prostaglandin synthesis. Stimulation of alpha-adrenoceptors by dihydroergotamine and of 5-HT receptors by ergotamine was confirmed on human hand veins in situ. Prejunctional receptors at sympathetic nerve terminals are involved in the regulation of venous tone. Inhibitory alpha-adrenoceptors, dopamine and PGE2 receptors as well as facilitating beta-adrenoceptor existing at human vasoconstrictor nerves may be stimulated or blocked by pharmacologic drugs thereby modifying venous tone.
Download full-text PDF |
Source |
|---|
Publication Analysis
Top Keywords
Similar Publications
Inferior vena cava diameter in patients with chronic heart failure and chronic kidney disease: a retrospective study.
Eur J Med Res
January 2025
Medical Big Data Research Center, Medical Innovation Research Division, Chinese PLA General Hospital, 28 Fuxing RD., Beijing, 100853, China.
Background: Chronic kidney disease (CKD) carries the highest population attributable risk for mortality among all comorbidities in chronic heart failure (CHF). No studies about the association between inferior vena cava (IVC) diameter and all-cause mortality in patients with the comorbidity of CKD and CHF has been published.
Methods: In this retrospective cohort study, a total of 1327 patients with CHF and CKD were included.
Factors Associated With Prolonged Venous Transit in Large Vessel Occlusion Acute Ischemic Strokes.
J Neuroimaging
January 2025
Department of Radiology, Division of Neuroradiology, Johns Hopkins Medical Center, Baltimore, Maryland, USA.
Background And Purpose: Prolonged venous transit (PVT), derived from computed tomography perfusion (CTP) time-to-maximum (T) maps, reflects compromised venous outflow (VO) in acute ischemic stroke due to large vessel occlusion (AIS-LVO). Poor VO is associated with worse clinical outcomes, but pre-treatment markers predictive of PVT are not well described.
Methods: We conducted a retrospective analysis of 189 patients with anterior circulation AIS-LVO who underwent baseline CT evaluation, including non-contrast CT, CT angiography, and CTP.
Getting closer to the coronary arteries: A bibliometric analysis of CT-based adipose tissue imaging in coronary artery disease.
Medicine (Baltimore)
November 2024
Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang, Hangzhou, China.
The aim of this study is to conduct a comprehensive bibliometric analysis of CT-based adipose tissue imaging related to coronary artery disease (CAD) to investigate the dynamic development of this field. Web of Science Core Collection was used as our data source to identify relevant documents limited to articles or review articles and written in English with no time restrictions. Then we analyzed the whole trend of publications and utilized VOSviewer and Bibliometrix to conduct a bibliometric analysis including citations, keywords, countries, institutions, authors as well as co-citation analyses of cited references and sources.
View Article and Find Full Text PDF[A case of pacemaker implantation via internal jugular vein in a patient with bilateral subclavian vein occlusion].
Zhonghua Xin Xue Guan Bing Za Zhi
January 2025
Department of Cardiology, Yangzhou Hospital of Traditional Chinese Medicine, Yangzhou225001, China.
May-Thurner Syndrome: An Unusual Case of Unilateral Severe Deep Vein Thrombosis in a Middle-Aged Women.
Cureus
December 2024
Critical Care Medicine, NMC Specialty Hospital, Abu Dhabi, ARE.
A 50-year-old female presented with a 10-day history of progressive swelling and pain in the left lower extremity, ultimately diagnosed with deep vein thrombosis (DVT) and May-Thurner Syndrome (MTS). Initial ultrasound indicated thrombosis involving the left external iliac, femoral, and popliteal veins, among others. Blood tests revealed normocytic anemia, but thrombophilia screening and other blood markers were normal.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!