The release of neuropeptides from dense-core vesicles (DCVs) is crucial in the nervous system. We previously identified RAB3 as a specific regulator of neuropeptide secretion in hippocampal neurons, as the ablation of all four RAB3 paralogs leads to a total block of DCV exocytosis. However, it is unknown whether this phenotype is conserved across different neuronal cell types. Here, we investigate potentially divergent regulatory mechanisms of RAB proteins governing DCV exocytosis in distinct neuronal populations. Our study identifies RAB3A as the key regulator of DCV exocytosis in hypothalamic and glutamatergic hippocampal neurons, while in hippocampal and striatal GABAergic cell populations, RAB3A is dispensable. Interestingly, loss of RAB27B, a protein closely related to RAB3, results in strongly reduced DCV exocytosis in striatal neurons but not in hippocampal neurons. Overexpression of RAB27B also effectively restores DCV exocytosis in RAB3A-deficient hippocampal neurons. Preliminary data indicate distinct expression patterns of RAB3A and RAB27B across neuronal populations, with higher levels of RAB3A in hippocampal and higher RAB27B levels in striatal neurons. Using single-cell sequencing analysis, we identify regulatory and effector proteins that may account for the observed cell-specific preferences for RAB3A and RAB27B. Our data show that neuropeptide secretion mechanisms are cell-type specific, with RAB3A as the main regulator of DCV release in hippocampal (glutamatergic) neurons and RAB27B in striatal (GABAergic) neurons. Furthermore, this work provides new insights into how RAB proteins function and are regulated in neurons.