Neuropeptide Y-like immunoreactivity in cultured intrinsic neurones of the heart.

A novel culture preparation from the atria of newborn guinea-pig hearts was employed to study the intrinsic innervation of the heart under conditions of unequivocal extrinsic denervation. Using an indirect immunofluorescence technique, a subpopulation of intracardiac neurones grown in dissociated cell culture was demonstrated to contain neuropeptide Y (NPY)-like immunoreactivity. This shows that NPY is not confined to sympathetic nerves. Further, since no endogenous catecholamines could be demonstrated in neurone cell bodies in the culture preparation with fluorescence histochemistry, confirming previous studies in situ, the findings also suggest that NPY does not coexist with catecholamine in these intrinsic heart neurones.