The function of presynaptic imidazoline-1 receptors (I1-R) in the heart remains unclear. In rat hearts, UK14.304 and moxonidine reduced norepinephrine (NE) release. AGN192403 had no influence on NE, whereas rilmenidine, agmatine, rauwolscine, and efaroxan increased NE. These effects of moxonidine and rilmenidine were not affected by AGN192403 adminstration. Conversely, after pretreatment with UK14.304, only moxonidine displayed a pronounced inhibitory action on NE release (sensitive to AGN192403), indicating a synergistic inhibitory action at I1-R under conditions of a stimulated alpha2-adrenergic autoinhibition.
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http://dx.doi.org/10.1196/annals.1304.033 | DOI Listing |
Life Sci
January 2023
Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt.
Aims: Reduced cardiac autophagy, ischemic injury, sympathetic overactivity, and apoptosis all contribute to metabolic syndrome (MetS)-associated cardiovascular risks. NR4A2, an orphan nuclear receptor NR4A family member, induces autophagy while suppressing apoptosis in myocardial infarction. Moxonidine, a sympathoinhibitor imidazoline1 receptor (I1R) agonist, has beneficial metabolic and hemodynamic effects; however, whether autophagy and/or NR4A2 signaling are involved in moxonidine's cardiovascular effects via I1R activation, is unknown, and is the aim of this study.
View Article and Find Full Text PDFNeuropsychopharmacology
July 2023
3Z, Reykjavik, Iceland.
iScience
April 2022
Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, WC1E 6BT London, UK.
Astrocytic GLT-1 is the main glutamate transporter involved in glutamate buffering in the brain, pivotal for glutamate removal at excitatory synapses to terminate neurotransmission and for preventing excitotoxicity. We show here that the surface expression and function of GLT-1 can be rapidly modulated through the interaction of its N-terminus with the nonadrenergic imidazoline-1 receptor protein, Nischarin. The phox domain of Nischarin is critical for interaction and internalization of surface GLT-1.
View Article and Find Full Text PDFPLoS One
February 2022
Department of Physiology, The Nippon Dental University School of Life Dentistry at Tokyo, Tokyo, Japan.
Purpose: We examined the cardiorespiratory effect of dexmedetomidine, an α2- adrenoceptor/imidazoline 1 (I1) receptor agonist, in spontaneously breathing adult rats.
Methods: Male rats (226-301 g, n = 49) under isoflurane anesthesia had their tail vein cannulated for drug administration and their tail artery cannulated for analysis of mean arterial pressure (MAP), pulse rate (PR), and arterial blood gases (PaO2, PaCO2, pH). After recovery, one set of rats received normal saline for control recording and was then divided into three experimental groups, two receiving dexmedetomidine (5 or 50 μg·kg-1) and one receiving normal saline (n = 7 per group).
Neurosci Lett
September 2021
Department of Physiology, The Nippon Dental University, School of Life Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan.
The activation of imidazoline 1 (I) receptors is suggested to stimulate the respiratory drive in newborn rats. Here, we immunohistochemically examined whether nischarin, an I receptor candidate protein, is expressed in the ventrolateral medulla, where cardiorespiratory centers are located. Newborn rats (age, 3-5 days) were deeply anesthetized with isoflurane; the brainstem was dissected, sectioned sagittally, and labeled with nischarin.
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