The secretion of molecules (e.g. neuropeptides, insulin-related peptides or neuromodulators such as serotonin and dopamine) contained within a postsynaptic dense core vesicle by fusion of the granule with the plasma membrane of the postsynapse in response to increased cytosolic calcium levels. [ GOC:aruk http://www.ncbi.nlm.nih.gov/pubmed/19448629 GOC:bc ]