d[Leu4,Lys8]-VP TFA is a selective agonist for the vasopressin V1b receptor (AVPR1B). Used primarily in research settings to study V1b receptor activity and signaling pathways. It is a modified peptide analog of vasopressin that helps in understanding the role of the V1b receptor in physiological processes such as stress response, corticotropin release, social behavior, and cognition. The compound is often utilized in in vitro and in vivo experiments to explore its effects on cellular mechanisms and receptor binding. Its application extends to pharmacological studies aiming to develop therapeutic agents targeting V1b-related disorders, including anxiety, depression, and stress-related conditions. Additionally, it serves as a tool in neuroendocrinology to investigate the impact of vasopressin on behavior and cognition.