These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Adenosine receptor-mediated relaxation of porcine coronary artery in presence and absence of endothelium.
    Author: Abebe W, Makujina SR, Mustafa SJ.
    Journal: Am J Physiol; 1994 May; 266(5 Pt 2):H2018-25. PubMed ID: 8203600.
    Abstract:
    This study was designed to investigate the effects of a series of adenosine analogues on porcine coronary artery in vitro. In both endothelium-intact and -denuded rings, 5'-(N-ethylcarboxamido) adenosine (NECA), 2-[p-(2-carboxyethyl)]phenylethylamino-5'-N-ethylcarboxamidoadenos ine (CGS-21680), 2-chloroadenosine (CAD), N6-R-phenylisopropyladenosine (R-PIA), 2-phenylaminoadenosine (PAA), N6-cyclohexyladenosine (CHA), N6-cyclopentyladenosine (CPA), and N6-S-phenylisopropyladenosine (S-PIA) produced concentration-dependent relaxations. The rank order of potency was consistent with A2-adenosine receptor identification. The xanthine adenosine antagonist, 8-(sulfophenyl) theophylline (8-SPT), attenuated the relaxant responses to all the agonists in the endothelium-intact rings and to only CAD, R-PIA, PAA, CHA, CPA, and S-PIA in the denuded preparations. Except for NECA and CGS-21680, the slopes of the relaxation curves and the dissociation constant (Kb) values for 8-SPT were similar for all agonists. In addition, endothelium removal selectively reduced the responses to NECA and CGS-21680. The adenosine receptor agonist, CGS-22988, also relaxed the denuded rings in a manner insensitive to blockade by 8-SPT. The data suggest that multiple A2-adenosine receptors exist on the smooth muscle and endothelium of porcine coronary artery, mediating relaxation. Whereas the smooth muscle contains both xanthine-sensitive and -insensitive A2-receptors, which can be activated by a wide range of adenosine agonists, the endothelium possesses xanthine-sensitive receptors that can be stimulated selectively by certain adenosine agonists, including 5'-uronamide derivatives, such as NECA and CGS-21680. The smooth muscle also appears to contain xanthine-insensitive A4-receptors activated by CGS-22988.(ABSTRACT TRUNCATED AT 250 WORDS)
    [Abstract] [Full Text] [Related] [New Search]