Bronchial Arteries
Biased signaling pathways in beta2-adrenergic receptor characterized by 19F-NMR. (1/3)
(+info)Nitric oxide and beta-adrenergic agonist-induced bronchial arterial vasodilation. (2/3)
In anesthetized sheep, we measured bronchial blood flow (Qbr) by an ultrasonic flow probe to investigate the interaction between inhaled nitric oxide (NO; 100 parts/million) given for 5 min and 5 ml of aerosolized isoetharine (1.49 x 10(-2) M concentration). NO and isoetharine increased Qbr from 26.5 +/- 6.5 to 39.1 (SE) +/- 10.6 and 39.7 +/- 10.7 ml/min, respectively (n = 5). Administration of NO immediately after isoetharine further increased Qbr to 57.3 +/- 15.1 ml/min. NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME; 30 mg/kg, in 20 ml saline given i.v.) decreased Qbr to 14.6 +/- 2.6 ml/min. NO given three times alternately with isoetharine progressively increased Qbr from 14.6 +/- 2.6 to 74.3 +/- 17.0 ml/min, suggesting that NO and isoetharine potentiate vasodilator effects of each other. In three other sheep, after L-NAME three sequential doses of isoetharine increased Qbr from 10.2 +/- 3.4 to 11.5 +/- 5.7, 11.7 +/- 4.7, and 13.3 +/- 5.7 ml/min, respectively, indicating that effects of isoetharine are predominantly mediated through synthesis of NO. When this was followed by three sequential administrations of NO, Qbr increased by 146, 172, and 185%, respectively. Thus in the bronchial circulation, there seems to be a close interaction between adenosine 3',5'-cyclic monophosphate- and guanosine 3',5'-cyclic monophosphate-mediated vasodilation. (+info)Non-cAMP-mediated bronchial arterial vasodilation in response to inhaled beta-agonists. (3/3)
We studied the dose-dependent effects of inhaled isoetharine HCl, a beta-adrenergic bronchodilator (2.5, 5.0, 10.0, and 20.0 mg), on bronchial blood flow (Qbr) in anesthetized sheep. Isoetharine resulted in a dose-dependent increase in Qbr. With a total dose of 17.5 mg, Qbr increased from baseline values of 22 +/- 3.4 (SE) to 60 +/- 16 ml/min (P < 0.001), an effect independent of changes in cardiac output and systemic arterial pressure. To further study whether synthesis of endogenous nitric oxide (NO) affects beta-agonist-induced increases in Qbr, we administered isoetharine (20 mg) by inhalation before and after the NO-synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME). Intravenous L-NAME (30 mg/kg) rapidly decreased Qbr by approximately 80% of baseline, whereas L-NAME via inhalation (10 mg/kg) resulted in a delayed and smaller (approximately 22%) decrease. Pretreatment with L-NAME via both routes of administration attenuated bronchial arterial vasodilation after subsequent challenge with isoetharine. We conclude that isoetharine via inhalation increases Qbr in a dose-dependent manner and that beta-agonist-induced relaxation of vascular smooth muscle in the bronchial vasculature is partially mediated via synthesis of NO. (+info)Isoetharine is a selective beta-2 adrenergic agonist, which is a type of medication that works by stimulating the beta-2 receptors in the smooth muscle of the airways. This leads to relaxation of the muscles and increased clearance of mucus from the airways, making it easier to breathe.
Isoetharine is used as a bronchodilator to treat conditions such as asthma, chronic obstructive pulmonary disease (COPD), and other respiratory disorders that cause narrowing of the airways. It is available in the form of an inhalation solution or aerosol for use with a nebulizer.
Like other beta-2 agonists, isoetharine can cause side effects such as tremors, palpitations, and increased heart rate. It should be used with caution in people with heart disease, high blood pressure, diabetes, or hyperthyroidism.
Metaproterenol is a short-acting, selective beta-2 adrenergic receptor agonist. It is primarily used as a bronchodilator to treat and prevent bronchospasms associated with reversible obstructive airway diseases such as asthma, chronic bronchitis, and emphysema. Metaproterenol works by relaxing the smooth muscles in the airways, thereby opening up the air passages and making it easier to breathe. It is available in oral (tablet or liquid) and inhalation (aerosol or solution for nebulization) forms. Common side effects include tremors, nervousness, headache, tachycardia, and palpitations.
Amino alcohols are organic compounds containing both amine and hydroxyl (alcohol) functional groups. They have the general structure R-NH-OH, where R represents a carbon-containing group. Amino alcohols can be primary, secondary, or tertiary, depending on the number of alkyl or aryl groups attached to the nitrogen atom.
These compounds are important in many chemical and biological processes. For example, some amino alcohols serve as intermediates in the synthesis of pharmaceuticals, dyes, and polymers. In biochemistry, certain amino alcohols function as neurotransmitters or components of lipids.
Some common examples of amino alcohols include:
* Ethanolamine (monoethanolamine, MEA): a primary amino alcohol used in the production of detergents, emulsifiers, and pharmaceuticals
* Serinol: a primary amino alcohol that occurs naturally in some foods and is used as a flavoring agent
* Choline: a quaternary ammonium compound with a hydroxyl group, essential for human nutrition and found in various foods such as eggs, liver, and peanuts
* Trimethylamine (TMA): a tertiary amino alcohol that occurs naturally in some marine animals and is responsible for the "fishy" odor of their flesh.
The bronchial arteries are a pair of arteries that originate from the descending thoracic aorta and supply oxygenated blood to the bronchi, bronchioles, and connected tissues within the lungs. They play a crucial role in providing nutrients and maintaining the health of the airways in the respiratory system. The bronchial arteries also help in the defense mechanism of the lungs by delivering immune cells and participating in the process of angiogenesis (the formation of new blood vessels) during lung injury or repair.
Catechols are a type of chemical compound that contain a benzene ring with two hydroxyl groups (-OH) attached to it in the ortho position. The term "catechol" is often used interchangeably with "ortho-dihydroxybenzene." Catechols are important in biology because they are produced through the metabolism of certain amino acids, such as phenylalanine and tyrosine, and are involved in the synthesis of various neurotransmitters and hormones. They also have antioxidant properties and can act as reducing agents. In chemistry, catechols can undergo various reactions, such as oxidation and polymerization, to form other classes of compounds.
Sympathomimetic drugs are substances that mimic or stimulate the actions of the sympathetic nervous system. The sympathetic nervous system is one of the two divisions of the autonomic nervous system, which regulates various automatic physiological functions in the body. The sympathetic nervous system's primary function is to prepare the body for the "fight-or-flight" response, which includes increasing heart rate, blood pressure, respiratory rate, and metabolism while decreasing digestive activity.
Sympathomimetic drugs can exert their effects through various mechanisms, including directly stimulating adrenergic receptors (alpha and beta receptors) or indirectly causing the release of norepinephrine and epinephrine from nerve endings. These drugs are used in various clinical settings to treat conditions such as asthma, nasal congestion, low blood pressure, and attention deficit hyperactivity disorder (ADHD). Examples of sympathomimetic drugs include epinephrine, norepinephrine, dopamine, dobutamine, albuterol, pseudoephedrine, and methylphenidate.
It is important to note that sympathomimetic drugs can also have adverse effects, particularly when used in high doses or in individuals with certain medical conditions. These adverse effects may include anxiety, tremors, palpitations, hypertension, arrhythmias, and seizures. Therefore, these medications should be used under the close supervision of a healthcare provider.