A study on the change of myocardial neuropeptide Y release induced by electric stimulation and myocardial ischemia in guinea pig heart

Electrical stimulation of the left stellate ganglion in guinea pig heart evoked a calcium-dependent, exocytotic release of neuropeptide Y (NPY). Stimulation after 10 min of global ischemia (S2), compared with control period stimulation (S1), had no signifcant effect on the NPY release. The release of NPY produced by the same stimulation fter 20 min of ischemia was inhibited to certain extent (S2/S1: 0.72, P0.05),whereas the inhibition of NPY release disappeared after 5 min of reper fusion (with a S2/S1 of 1.01). Ischemia alone, without electric stimulation, did not apparently induce NPY release, suggesting that electrical Stimulation may induce a calcium-dependent, exocytotic release of NPY. It is further suggested that the inhibion of NPY release may be produced by some metubolites and the abolishment of the inhibion after reperfusionmay be due to washout of the metubolites.