Adenosine triphosphate - Established and potential clinical applications

Adenosine 5'-triphosphate (ATP) is a purine nucleotide found in every cell of the human body. In addition to its well established role in cellular met abolism, extracellular ATP and its breakdown product adenosine, exert prono unced effects in a variety of biological processes including neurotransmiss ion, muscle contraction, cardiac function, platelet function, vasodilatatio n and liver glycogen metabolism. These effects are mediated by both P1 and P2 receptors. A cascade of ectonucleotidases plays a role in the effective regulation of these processes and may also have a protective function by ke eping extracellular ATP and adenosine levels within physiological limits. I n recent years several clinical applications of ATP and adenosine have been reported. In anaesthesia, low dose adenosine reduced neuropathic pain, hyp eralgesia and ischaemic pain to a similar degree as morphine or ketamine. P ostoperative opioid use was reduced. During surgery, ATP and adenosine have been used to induce hypotension. In patients with haemorrhagic shock, incr eased survival was observed after ATP treatment. In cardiology, ATP has bee n shown to be a well tolerated and effective pulmonary vasodilator in patie nts with pulmonary hypertension. Bolus injections of ATP and adenosine are useful in the diagnosis and treatment of paroxysmal supraventricular tachyc ardias. Adenosine also allowed highly accurate diagnosis of coronary artery disease. In pulmonology, nucleotides in combination with a sodium channel blocker improved mucociliary clearance from the airways to near normal in p atients with cystic fibrosis. In oncology, there are indications that ATP m ay inhibit weight loss and tumour growth in patients with advanced lung can cer. There are also indications of potentiating effects of cytostatics and protective effects against radiation tissue damage. Further controlled clin ical trials are warranted to determine the full beneficial potential of ATP , adenosine and uridine 5'-triphosphate.