THE CHRONOTROPIC ACTION OF ATP AND RELATED COMPOUNDS STUDIED BY DIRECT PERFUSION OF THE SINUS NODE

摘要: ATP has an immediately profound but relatively transient negative chronotropic effect on direct perfusion of the sinus node dog. This is not altered by atropine. Adenosine, A5MP and ADP have actions similar to ATP. Adenine creatine phosphate no significant action. Therefore, in bonds are essential its action D-ribose chain is. Inosine, which action, differs from adenosine only having a hydroxyl group instead amino at 6-carbon position. both necessary for (and ATP). Guanosine principally location 2-carbon 6-carbon, (acceleration) opposite that adenosine. position important influence these purine nucleosides. A2MP, A3MP cyclic AMP all being slower onset less marked maximal degree longer duration. adenine nucleotides modifies nature their action. Two pyrimidine nucleosides (cytidine uridine) The nucleotide inosine active, resembling ATP, while not. guanosine inactive, accelerates node, unaffected beta -receptor blockade. significance different uncertain. DNP produces gradual development bradycardia atropine. DNP reversible with reversed CP (although consistently). Reversal indicates canine can utilize as energy source. On basis present studies plus previous ones this laboratory, light other recent observations, it suggested dipyridamole due adenosine-sparing effect. The possible relative pathophysiology depressed function some cases human acute myocardial infarction discussed.