title: Effects of enprofylline and theophylline may show the role of adenosine.
abstract: It is well established that at low and clinically relevant concentrations theophylline (and caffeine) exerts antagonism at cell surface receptor sites for adenosine. However, it is not known which actions of theophylline are due to adenosine antagonism, because theophylline apparently activates other cellular mechanisms at the same low concentrations. Investigations into the actions of xanthines and their structure activity relationships have identified xanthine compounds like enprofylline (3-propylxanthine) that only has some actions in common with theophylline and that has a negligible ability to antagonize adenosine. Enprofylline is a more potent smooth muscle relaxant and antiasthmatic drug than theophylline but does not produce, e.g., theophylline-like diuretic effects, CNS-stimulant behavioural effects (restlessness - seizures), gastric secretory effects and release of free fatty acids. It is proposed that pharmacodynamic dissimilarities between enprofylline and theophylline may indicate physiological roles of adenosine.
mesh_terms: D000241:Adenosine / Q000037:antagonists & inhibitors / Q000502:physiology*; D000818:Animals; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology; D001921:Brain / Q000187:drug effects / Q000502:physiology; D001993:Bronchodilator Agents; D002110:Caffeine / Q000494:pharmacology; D004231:Diuresis / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005744:Gastric Acid / Q000378:metabolism; D006321:Heart / Q000187:drug effects; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D008168:Lung / Q000187:drug effects / Q000502:physiology; D009318:Natriuresis / Q000187:drug effects; D010726:Phosphodiesterase Inhibitors; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000502:physiology; D011983:Receptors, Purinergic; D012119:Respiration / Q000187:drug effects; D013189:SRS-A / Q000037:antagonists & inhibitors; D012640:Seizures / Q000139:chemically induced; D013806:Theophylline / Q000009:adverse effects / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014970:Xanthines / Q000009:adverse effects / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D001993:Bronchodilator Agents; D005230:Fatty Acids, Nonesterified; D010726:Phosphodiesterase Inhibitors; D011956:Receptors, Cell Surface; D011983:Receptors, Purinergic; D013189:SRS-A; D014970:Xanthines; D002110:Caffeine; D013806:Theophylline; C034347:enprofylline; D000241:Adenosine