Effect of theophylline on adenosine production in the canine myocardium
Adenosine is thought to participate in local regulation of coronary blood flow. However, competitive antagonists of adenosine fail to block myocardial active hyperemia. The authors examined the effect of locally administered theophylline on active hyperemia and myocardial adenosine production during intracoronary isoproterenol infusion in the dog heart. Isoproterenol decreased coronary resistance and increased myocardial adenosine production. Infusion of theophylline at a rate that attenuated the vasodilator response to exogenously administered adenosine failed to attenuate the increase in coronary blood flow produced by isoproterenol. However, theophylline plus isoproterenol production greater increases in myocardial adensine production than isoproterenol alone. The curves relating resistance and adenosine in the presence of theophylline fell to the right of those in the absence of theophylline. These findings suggest that the failure of theophylline to attenuate isoproterenol hyperemia in the dog heart results at least in part from an increase in adenosine concentration at the arteriole to a level beyond that blocked by this competitive antagonist and that adenosine may in fact play a role in isoproterenol-induced active hyperemia.
- Research Organization:
- Uniformed Services Univ. of the Health Sciences, Bethesda, MD
- OSTI ID:
- 6469641
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 252:1
- Country of Publication:
- United States
- Language:
- English
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RADIOASSAY
THEOPHYLLINE
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CERIUM 141
DOGS
MYOCARDIUM
STRONTIUM 85
THIN-LAYER CHROMATOGRAPHY
ALKALINE EARTH ISOTOPES
ANIMALS
AROMATICS
AZAARENES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
CERIUM ISOTOPES
CHEMISTRY
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
HEART
HETEROCYCLIC COMPOUNDS
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MUSCLES
NUCLEI
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANS
PURINES
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RARE EARTH ISOTOPES
RARE EARTH NUCLEI
RIBOSIDES
SEPARATION PROCESSES
STRONTIUM ISOTOPES
VASODILATORS
VERTEBRATES
XANTHINES
550601* - Medicine- Unsealed Radionuclides in Diagnostics