Thrombin activation of the Na+/H+ exchanger in vascular smooth muscle cells. Evidence for a kinase C-independent pathway which is Ca2+-dependent and pertussis toxin-sensitive

Chou-Long Huang; Martin G Cogan; Edward J Cragoe Jr; Harlan E Ives

doi:10.1016/S0021-9258(18)47914-8

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Thrombin activation of the Na+/H+ exchanger in vascular smooth muscle cells. Evidence for a kinase C-independent pathway which is Ca2+-dependent and pertussis toxin-sensitive

Journal article

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Peer reviewed

Thrombin activation of the Na+/H+ exchanger in vascular smooth muscle cells. Evidence for a kinase C-independent pathway which is Ca2+-dependent and pertussis toxin-sensitive

Chou-Long Huang, Martin G Cogan, Edward J Cragoe Jr and Harlan E Ives

The Journal of biological chemistry, Vol.262(29), pp.14134-14140

10/15/1987

DOI: 10.1016/S0021-9258(18)47914-8

PMID: 2820995

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Abstract

The mechanism by which human alpha-thrombin activates the Na+/H+ exchanger was studied in cultured neonatal rat aortic smooth muscle cells. Thrombin (0.4 unit/ml) caused a rapid cell acidification followed by a slow, amiloride-inhibitable alkalinization (0.10-0.14 delta pHi above base line). In protein kinase C down-regulated cells (exposed to phorbol 12-myristate 13-acetate for 24 or 72 h), the delta pHi induced by thrombin was only partially attenuated. This protein kinase C-independent activation of the Na+/H+ exchanger was blocked by pertussis toxin (islet activating protein (IAP)), reducing delta pHi by 50%. IAP did not directly inhibit Na+/H+ exchange activity as assessed by the response to intracellular acid loading. Thrombin also stimulated arachidonic acid release by 2.5 fold and inositol trisphosphate release by 6.2 fold. IAP inhibited both of these activities by 50-60%. Intracellular Ca2+ chelation with 120 microM quin2 prevented the thrombin-induced Ca2+ spike, inhibited thrombin-induced arachidonic acid release by 75%, and inhibited thrombin-induced activation of the Na+/H+ exchanger in protein kinase C-deficient cells by 65%. Increased intracellular [Ca2+] alone was not sufficient to activate the Na+/H+ exchanger, since ionomycin (0.3-1.5 microM) failed to elevate cell pH significantly. 10 microM indomethacin inhibited thrombin-induced delta pHi in both control and protein kinase C down-regulated cells by 30-50%. Thus, thrombin can activate the Na+/H+ exchanger in vascular smooth muscle cells by a Ca2+-dependent, pertussis toxin-sensitive pathway which does not involve protein kinase C.

Animals

Animals, Newborn

Arachidonic Acid

Arachidonic Acids - biosynthesis

Calcium - pharmacology

Carrier Proteins - metabolism

Cells, Cultured

Ethers - pharmacology

Humans

Ionomycin

Kinetics

Muscle, Smooth, Vascular - metabolism

Pertussis Toxin

Protein Kinase C - metabolism

Rats

Sodium-Hydrogen Exchangers

Thrombin - pharmacology

Virulence Factors, Bordetella - pharmacology

Details

Title: Subtitle: Thrombin activation of the Na+/H+ exchanger in vascular smooth muscle cells. Evidence for a kinase C-independent pathway which is Ca2+-dependent and pertussis toxin-sensitive
Creators: Chou-Long Huang - University of California, San Francisco
Martin G Cogan - University of California, San Francisco
Edward J Cragoe Jr
Harlan E Ives - University of California, San Francisco
Resource Type: Journal article
Publication Details: The Journal of biological chemistry, Vol.262(29), pp.14134-14140
DOI: 10.1016/S0021-9258(18)47914-8
PMID: 2820995
NLM abbreviation: J Biol Chem
ISSN: 0021-9258
eISSN: 1083-351X
Grant note: DK34127 / NIDDK NIH HHS DK37423 / NIDDK NIH HHS DK27045 / NIDDK NIH HHS
Language: English
Date published: 10/15/1987
Academic Unit: Nephrology; Internal Medicine
Record Identifier: 9984359681102771

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