scholarly journals Evaluation of the Effect of a Novel β3-Adrenergic Agonist on Choroidal Vascularity

2021 ◽  
Vol 62 (9) ◽  
pp. 17
Author(s):  
Murat Topcuoglu ◽  
Fatih Aslan
Keyword(s):  
Author(s):  
L.S. Cutler

Many studies previously have shown that the B-adrenergic agonist isoproterenol and the a-adrenergic agonist norepinephrine will stimulate secretion by the adult rat submandibular (SMG) and parotid glands. Recent data from several laboratories indicates that adrenergic agonists bind to specific receptors on the secretory cell surface and stimulate membrane associated adenylate cyclase activity which generates cyclic AMP. The production of cyclic AMP apparently initiates a cascade of events which culminates in exocytosis. During recent studies in our laboratory it was observed that the adenylate cyclase activity in plasma membrane fractions derived from the prenatal and early neonatal rat submandibular gland was retractile to stimulation by isoproterenol but was stimulated by norepinephrine. In addition, in vitro secretion studies indicated that these prenatal and neonatal glands would not secrete peroxidase in response to isoproterenol but would secrete in response to norepinephrine. In contrast to these in vitro observations, it has been shown that the injection of isoproterenol into the living newborn rat results in secretion of peroxidase by the SMG (1).


1986 ◽  
Vol 113 (4) ◽  
pp. 471-478 ◽  
Author(s):  
R. J. Kemppainen ◽  
J. L. Sartin

Abstract. In order to examine regulation of pituitary intermediate lobe secretion, plasma immunoreactive (i)ACTH, cortisol, and α-MSH responses to iv bolus injections of CRF, quipazine maleate (serotonin agonist), isoproterenol (β-adrenergic agonist) or haloperidol (dopamine antagonist) were determined in conscious, unrestrained dogs. Endocrine responses to these test substances were also determined in dogs pre-treated with dexamethasone. Administration of one or more doses of each test substance resulted in significant elevations in plasma iACTH and cortisol concentrations. Only haloperidol injection caused significant increases in plasma iα-MSH. Following dexamethasone pre-treatment, plasma iACTH and cortisol increases in response to all test substances were considerably reduced or abolished. Dexamethasone did not alter baseline or haloperidol-stimulated plasma ia-MSH concentrations. However, infusion of bromocriptine mesylate (dopamine agonist) in combination with dexamethasone pre-treatment reduced the plasma iα-MSH response to haloperidol. We conclude that a dopaminergic pathway is important in the in vivo regulation of pituitary intermediate lobe activity in dogs.


1986 ◽  
Vol 1 (3) ◽  
pp. 234-236
Author(s):  
B. Bondy ◽  
M. Ackenheil ◽  
G. Laakmann ◽  
H.T. Munz

SummaryThe influence of subchronic application of the β-adrenergic agonist clenbuterol on plasma norepinephrine (NE), epinephrine (E) and β-receptors on lymphocytes was investigated in 8 male, healthy volunteers. Treatment with clenbuterol (0.04 mg/day) for 6 days induced significant reduction of β-receptor specific binding in 7 of the 8 subjects with a mean decrease of 40% (p < 0.01) with no changes in affinity. Concomitantly an increase in the plasma NE concentration was observed (mean 50%, p < 0.01), but no significant overall alteration of E concentration. Our results suggest that β-adrenergic agonists exercise a similar effect on the peripheral adrenergic system and on the adrenergic system in the brain.


1999 ◽  
Vol 276 (1) ◽  
pp. L1-L8 ◽  
Author(s):  
Edward Abraham ◽  
Debra J. Kaneko ◽  
Robert Shenkar

Endotoxemia produces elevations in catecholamine levels in the pulmonary and systemic circulation as well as rapid increases in neutrophil number and proinflammatory cytokine expression in the lungs. In the present experiments, we examined the effects of endogenous and exogenous adrenergic stimulation on endotoxin-induced lung neutrophil accumulation and activation. Levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and macrophage inflammatory protein (MIP)-2 mRNAs were increased in lung neutrophils from endotoxemic mice compared with those present in lung neutrophils from control mice or in peripheral blood neutrophils from endotoxemic or control mice. Treatment with the β-adrenergic antagonist propranolol before endotoxin administration did not affect trafficking of neutrophils to the lungs or the expression of IL-1β, TNF-α, or MIP-2 by lung neutrophils. Administration of the α-adrenergic antagonist phentolamine before endotoxemia did not alter lung neutrophil accumulation as measured by myeloperoxidase (MPO) levels but did result in significant increases in IL-1β, TNF-α, and MIP-2 mRNA expression by lung neutrophils compared with endotoxemia alone. Administration of the α1-adrenergic agonist phenylephrine before endotoxin did not affect trafficking of neutrophils to the lungs but was associated with significantly increased expression of TNF-α and MIP-2 mRNAs by lung neutrophils compared with that found after endotoxin alone. In contrast, treatment with the α2-adrenergic agonist UK-14304 prevented endotoxin-induced increases in lung MPO and lung neutrophil cytokine mRNA levels. The suppressive effects of UK-14304 on endotoxin-induced increases in lung MPO were not affected by administration of the nitric oxide synthase inhibitor N-nitro-l-arginine methyl ester. These data demonstrate that the initial accumulation and activation of neutrophils in the lungs after endotoxemia can be significantly diminished by α2-adrenergic stimulation. Therapy with α2-adrenergic agents may have a role in modulating inflammatory pulmonary processes associated with sepsis-induced acute lung injury.


2019 ◽  
Vol 217 (5) ◽  
pp. 932-936 ◽  
Author(s):  
Kristen E. Limbach ◽  
Mary E. Condron ◽  
Ann E. Bingham ◽  
SuEllen J. Pommier ◽  
Rodney F. Pommier

1990 ◽  
Vol 258 (1) ◽  
pp. R70-R76 ◽  
Author(s):  
S. Papas ◽  
P. Smith ◽  
A. V. Ferguson

Extracellular single-unit recordings from neurons in the area postrema (AP) and the nucleus tractus solitarius (NTS) in anesthetized male rats demonstrated that most cells in these regions have spontaneous activities of 5 Hz or less. Systemic angiotensin (ANG II) (50-500 ng) enhanced the activity of 55% of AP cells tested (n = 76), whereas 53% of tested NTS neurons (n = 62) were inhibited by ANG II. To determine whether these neurons were influenced specifically by circulating ANG II or by the accompanying increase in mean arterial blood pressure (BP), the effects of adrenergic agonists given intravenously on ANG II influenced neurons were also examined. Subsequently two cell types were characterized: cells responding to iv ANG II but not to the adrenergic agonist ("ANG II sensitive") and cells responding in a similar way to both agents ("BP sensitive"). Most ANG II-responsive neurons in the AP (53.5%) and the NTS (65%) were determined to be BP sensitive. These data demonstrate that ANG II influences the activity of AP neurons. In addition, there exists a second population of AP neurons apparently responsive to perturbations of the cardiovascular system. These studies further emphasize the potential roles of the AP in the regulation of body fluid balance.


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