Neurohumoral Regulation
Thomas F. Lüscher, Paul M. Vanhoutte in The Endothelium: Modulator of Cardiovascular Function, 2020
Although circulating substances obviously have an easy access to the endothelium, relatively few hormones evoke endothelium-dependent responses. This probably reflects that endothelium-dependent modulation of vascular tone is primarily a local regulatory mechanism. There are no indications that activation of α 1 -adrenergic receptors can lead to the release of endothelium-derived relaxing factor(s) (EDRFs), although a-adrenergic activation evokes the release of prostacyclin from the endothelium. n the canine and porcine coronary artery, in canine pulmonary and femoral arteries and veins, and in the aorta and tail artery of the rat norepinephrine and the selective α 2 -adrenergic agonist UK 14307 initiate endothelium-dependent relaxations. In the canine coronary artery and in the cerebral artery of the cat, no evidence could be obtained that acetylcholine released from cholinergic nerves activates endothelial receptors. Thus, although neurogenically released acetylcholine might evoke the release of EDRF at the microcirculatory level, it seems unlikely that this is the case in large conduit arteries.
Pseudoephedrine
James L. Schardein, Orest T. Macina in Human Developmental Toxicants, 2006
Pseudoephedrine is an adrenergic agonist widely used as a nasal and bronchial decongestant, often in combination with other drugs. It is present in plants of the genus Ephedra, known in traditional medicine as Ma Huang. The drug directly stimulates a-adrenergic receptors of respiratory mucosa, causing vasoconstriction, and β-adrenergic receptors, causing bronchial relaxation, increased heart rate, and contractility. Pseudoephedrine is available as an over-the-counter generic drug and has a large number of trade names, of which Sudafed® and some Dimetapp® formulations are among the most commonly used. Several earlier studies and several more recent studies, in contrast, found no association between first trimester exposure to pseudoephedrine and malformations of any type among more than 2600 pregnancies. Pseudoephedrine is a lower-sized molecule in comparison to the other compounds. It is of low polarity and of average hydrophobicity. Pseudoephedrine can engage in hydrogen bonding both as a hydrogen bond donor and acceptor.
Adrenergic Agents in Child and Adolescent Psychiatry
David Rosenberg in Pocket Guide For The Textbook Of Pharmacotherapy For Child And Adolescent psychiatric disorders, 1994
Ldonidine, an alpha-2 adrenergic agonist with known antihypertensive effi- cacy, has no established FDA recommendations for use in child and adoles- cent psychiatry. Because it activates presynaptic alpha-2 receptors-which, through their negative feedback action, results in the postsynaptic inhibition of central noradrenergic neurons-clonidine may be a particularly useful agent in psychiatry. It is currently under active investigation better to dis- cern its role in the treatment of children and adolescents. Thus far, it has been most studied with regard to Tourette's disorder, ADHD in children and adolescents, and the control of opiate withdrawal symptoms.
Beta
Published in Archives Internationales de Physiologie et de Biochimie, 1989
I. De Dios, J. J. Calvo, J. I. San Roman, M. A. Plaza, M. A. Lopez
The effect of Dobutamine (a β1-adrenergic agonist) and Terbutaline (a β2-adrenergic agonist) on exocrine pancreatic secretion was studied in anaesthetized rabbits, simultaneously controlling pancreatic blood flow and blood pressure. The secretion of fluid and ions (bicarbonate, sodium and potassium) was unaffected by the infusion of Dobutamine (8 μg.kg−1.min−1) or Terbutaline (10 μg.kg-1.min−1). Neither were pancreatic blood flow or mean blood pressure altered. Dobutamine or Terbutaline depress the function of the acinar cells, amylase secretion being more affected by the action of Terbutaline. The results show that β1 and β2-adrenergic stimulation has no effect on the ductular cells but does decrease the secretion by the acinar cells.
Dexmedetomidine: Exploring Its Potential Role and Dosing Guideline for Its Use in Intractable Pain in the Palliative Care Setting
Published in Journal of Pain & Palliative Care Pharmacotherapy, 2010
Patrick J. Coyne, Colin P. Wozencraft, Seth B. Roberts, Barton Bobb, Thomas J. Smith
ABSTRACT Intractable pain continues to pose problems for patients with life-limiting disease. The authors review the potential role of dexmedetomidine (Precedex), an α2-adrenergic agonist, as a bridge to obtaining effective analgesia. The authors offer criteria to consider in utilizing this medication within the context of palliative care.
Clonidine Antagonizes Pressor Effect of N-Methyl-D-Aspartate in the Rostral Ventrolateral Medulla of Rats
Published in Clinical and Experimental Hypertension, 1997
J. C. Lin, D. M. Liu, Yun Wang
The purpose of the present study was to investigate the modulatory actions of adrenoreceptor agonists on N-methyl-D-aspartate (NMDA)-induced pressor effect in rostral ventrolateral medulla (RVLM). These drugs were locally applied into RVLM of urethane-anesthetized Sprague-Dawley rats through multibarrel pipettes. Microinjection of NMDA increased the arterial pressure, an effect which was abolished by pretreatment with clonidine, whereas neither the β-adrenergic agonist isoproterenol nor the α1-adrenergic agonist phenylephrine did alter this pressor response. Previous experiments demonstrated that clonidine binds to noradrenergic α2 and imidazoline receptors in the RVLM. Norepinephrine, which has high affinity for the α2 receptor and low affinity to the imidazoline receptor, partially antagonized NMDA-induced hypertension. On the other hand, administration of selective imidazoline receptor antagonist idazoxan partially reversed clonidine-mediated antagonism of NMDA. Taken together, these results suggest that clonidine may modulate the excitatory amino acid -induced pressor response through noradrenergic α2 and imidazoline receptors in the RVLM.
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