Plasma level of norepinephrine and cyclic nucleotides following acute myocardial infarction

The plasma concentrations of norepinephrine (NE), adenosine cyclic 3', 5'-monophosphate (cyclic AMP), and guanosine cyclic 3', 5'-monophosphate (cyclic GMP) were measured serially for 2 weeks after the onset of symptoms in 17 patients with acute myocardial infarction (AMI). The mean concentrations of NE in patients without complications were significantly elevated during the first 2 days following AMI. There was a significant correlation between the maximum concentration of plasma NE and of plasma CK. The mean concentrations of plasma cyclic AMP and cyclic GMP in patients without complications were significantly elevated on the first day and for 8 days respectively following AMI. The concentration of plasma cyclic AMP on admission in patients with complications was significantly higher than that in those without complications. There were significant correlations between the maximum concentration of plasma cyclic AMP and those of plasma CK, GOT, and LDH. Significant but weak correlations between the concentration of plasma NE and those of cyclic AMP and cyclic GMP were found. The results of the present study suggest an enhanced sympathetic nervous system activity at an early stage of AMI, a prolonged enhancement of parasympathetic nervous system activity in the course of AMI, and the potential value of plasma cyclic AMP concentrations as a useful index to estimate the seriousness and size of AMI.