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peptidergic

a. Describing neurons that secrete peptide hormones as their neurotransmitters

Wikipedia
Peptidergic

Peptidergic, or peptidic, means "related to peptides".

A peptidergic agent (or drug) is a chemical which functions to directly modulate the peptide systems in the body or brain. An example is opioidergics, which are neuropeptidergics.