Opioid receptor in vascular smooth muscle.
Item
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Title
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Opioid receptor in vascular smooth muscle.
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Identifier
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AAI9959222
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identifier
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9959222
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Creator
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Saeed, Rubina Waheed.
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Contributor
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Adviser: Harold I. Magazine
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Date
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2000
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Cell | Biology, Animal Physiology | Biology, Neuroscience
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Abstract
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Opioid receptors have been extensively studied in the nervous system of mammals and invertebrates. Recently they have been demonstrated in inflammatory cells and in gastric smooth muscle cells. Opiates and endogenous opioids have been demonstrated to modulate blood pressure and responses to hypotension and hypothermia. Although these data suggest the potential for direct opioid regulation of vascular tone, opioid receptors have not been demonstrated in vascular smooth muscle. We used RT-PCR to evaluate delta opioid receptor (DOR) expression in the rat arterial smooth muscle cell line, A-10. We amplified and isolated a DNA fragment of expected size. Cloning and sequencing of the fragment revealed a sequence identical to the known DOR sequence from rat brain. Pharmacological studies were performed using human and rat vascular tissue. DOR competition studies demonstrated the presence of delta opioid selective receptors in vascular smooth muscle that was consistent with the delta 2 subtype. Immunocytochemical analysis using commercially available DOR antisera demonstrated the presence of DOR-binding site on A-10 cells.;To investigate receptor-signaling mechanisms, we employed confocal microscopic analysis and evaluated changes in membrane potential and intracellular calcium in response to DOR-activation. The DOR-selective agonist, DAMA, induced a 11.5mV membrane depolarization that was potentiated and inhibited by preincubation with the tyrosine phosphatase inhibitor, vanadate, and the tyrosine kinase inhibitor, erbstatin, respectively. Exposure of A-10 cells to DAMA stimulated an increase in intracellular calcium that was linked to ryanodyne-sensitive stores and extracellular calcium. Physiological characterization of the DOR was performed by evaluation of rat aortic rings. DAMA stimulates the contraction of rat aorta whereas preincubation with ryanodyne and naltrindole, potentiated and inhibited this response respectively.;These data taken together, demonstrate the presence of a functional DOR in vascular smooth muscle that is couple to the direct regulation of contractile tone.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
