関連する実験動画

Updated: Jul 26, 2026

Disrupting Reconsolidation of Fear Memory in Humans by a Noradrenergic β-Blocker
08:32

Disrupting Reconsolidation of Fear Memory in Humans by a Noradrenergic β-Blocker

Published on: December 18, 2014

低用量経口プロプラノロルの後のベータブロックと血中濃度:肝臓の"ファーストパス"の値が再検討されました

R Davies, T G Pickering, A Morganti

    Lancet (London, England)
    |February 25, 1978
    PubMed
    まとめ

    低用量プロプラノロルは,心拍数と血圧に対するイソプレナリンの効果を効果的に阻害し,ベータ阻害を示す. これは,ヒトにおける肝臓における提案された"ファーストパス効果"の値に異議を唱える.

    さらに関連する動画

    Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS08:38

    Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS

    Published on: November 8, 2015

    関連する概念動画

    Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers01:27

    Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers

    β-receptor blockers significantly impact the cardiovascular system by counteracting catecholamine-induced sympathetic responses. These medications decrease heart rate, contractility, and cardiac output, potentially leading to cardiac depression, life-threatening bradycardia, and death. Therapeutically, β-blockers function as mild antihypertensives and are utilized in treating angina pectoris and cardiac arrhythmias. However, nonselective β-blockers inhibit β2-receptors in bronchial smooth...
    Adrenergic Antagonists: ɑ and β-Receptor Blockers01:31

    Adrenergic Antagonists: ɑ and β-Receptor Blockers

    Third-generation β-blockers, such as labetalol and carvedilol, represent a significant advancement in managing cardiovascular conditions. Unlike conventional β-blockers, which can induce peripheral vasoconstriction, third-generation drugs block α1 adrenoceptors. This promotes vasodilation through several mechanisms, such as increased nitric oxide production, inhibition of calcium ion entry, opening of potassium ion channels, and antioxidant action. Labetalol, for instance, is clinically...
    First Pass Effect01:12

    First Pass Effect

    Presystemic elimination, or the first-pass effect, is the metabolism of drugs that reduces their effective concentration at the site of action. Apart from the first-pass effect, the systemic bioavailability of the drug is also reduced by other factors, including incomplete absorption or chemical degradation of drugs.
    Depending on the route of administration, drugs can be metabolized in the liver, intestine, lungs, and vasculature. Orally administered drugs are first absorbed through the...
    Antihypertensive Drugs: Types of β-Blockers01:28

    Antihypertensive Drugs: Types of β-Blockers

    β receptors are classified into three subclasses: β1, β2, and β3. β1 receptors are primarily located in the heart and kidneys. When they get activated, they increase heart rate, contractility, and renin release. This process enhances blood pressure and aids in stress management. In contrast, β2 receptors are situated mainly in the lungs, blood vessels, and skeletal muscles. Upon activation, they trigger smooth muscle relaxation, causing bronchodilation and vasodilation. This widens airways and...
    Factors Influencing Drug Absorption: Presystemic Elimination01:24

    Factors Influencing Drug Absorption: Presystemic Elimination

    The pharmacokinetic journey of oral drugs begins with a crucial first pass through the hepatic portal system, called the first-pass effect. This first pass significantly impacts bioavailability — the proportion of a drug that enters systemic circulation and is available for therapeutic action. The primary route sees the drug absorbed by intestinal membranes and then shunted to the liver via the hepatic portal vein. Here, pre-systemic elimination occurs as drugs face metabolism or biliary...
    Hepatic Drug Clearance: Effect of Protein Binding01:09

    Hepatic Drug Clearance: Effect of Protein Binding

    Hepatic clearance is influenced by protein binding based on the drug's extraction ratio. Drugs with high extraction ratios are considered flow-limited and remain unaffected by protein binding during hepatic clearance. On the other hand, drugs with low extraction ratios may be impacted by plasma protein binding, although the extent of this influence depends on the fraction of the drug bound.
    For low-extraction-ratio drugs that are less than 80% protein-bound, minor changes in protein binding...