PLASMA NEUROPEPTIDE-Y LEVELS IN THE ACUTE AND EARLY CONVALESCENT PHASE AFTER MYOCARDIAL-INFARCTION

The sympathetic nervous system is activated in acute myocardial infarc tion (MI). Scarce data exist, however, regarding the release of the sy mpathetic cotransmitter neuropeptide Y (NPY) during the acute and earl y convalescent phases after acute MI. Plasma NPY determination was obt ained on days 1 and 3 after admission from 47 patients with acute MI a nd from eight control patients with acute chest pain without MI. Sampl es were also obtained on day 30 from the 39 survivors from the origina l MI cohort. Plasma NPY peaked on day 3 in the MI group (day 1: mean = 46.0 pmol/L, SEM = 6.4 pmol/L; day 3: mean = 60.8 pmol/L, SEM = 5.7 p mol/L; day 30: mean = 27.2 pmol/L, SEM = 4.1 pmol/L; days 1 to 3: p = 0.002; days 3 to 30: p < 0.001), whereas in the control group a nonsig nificant decrease from day 1 (mean = 42.6 pmol/L, SEM = 12.3 pmol/L) t o day 3 (mean = 34.0 pmol/L, SEM = 5.6 pmol/L) was observed. Plasma NP Y levels were significantly increased in patients with MI on day 3 (p = 0.044), but not at baseline compared with the control group. No sign ificant association between plasma NPY and plasma catecholamines, clin ical heart failure, or 1-month survival was evident. These results sug gest that increased plasma levels of the vasoconstrictory and cardiode pressant sympathetic neurotransmitter NPY are present in the recovery phase of MI, but with a plasma profile distinct from that of catechola mines.