Hederagenin Attenuates Morphine Addiction via GABAA1-Mediated Modulation of Ca2 +-CaMK-CREB Signaling in Ventral Tegmental Dopaminergic Neurons.

Morphine-associated contextual reward learning promotes maladaptive drug-context associations during opioid exposure. Hederagenin (HE), a bioactive compound from traditional Chinese medicine, has neuroprotective potential, but its role in contextual reward learning remains unclear. Here, we investigated the effects of HE on morphine-induced conditioned place preference (CPP) acquisition and explored its target, downstream signaling, and brain-delivery strategy. HE attenuated morphine CPP acquisition in both sexes and reduced established CPP expression. Chemical proteomics identified the GABAA receptor α1 subunit (GABAA1, encoded by GABRA1) as a prioritized HE-associated target, supported by competitive pull-down, non-permeabilized HE-biotin labeling, microscale thermophoresis, cellular thermal shift assay, and molecular docking. Mechanistically, HE reduced c-Fos activation in ventral tegmental area (VTA) TH-positive dopaminergic neurons, attenuated reward-context-associated VTA calcium responses, suppressed intracellular Ca2 + elevation in SH-SY5Y cells, and reduced VTA CaMKII, PKA, and CREB phosphorylation. Animal-level analyses linked CPP scores to compartment-selective VTA calcium responses and p-CREB/CREB ratios, whereas TH+/c-Fos+ associations varied by treatment. Compared with non-targeted liposomes, RVG29-modified HE-loaded liposomes showed greater brain- and VTA-associated distribution and suppressed established CPP after a single administration. Together, these findings identify HE as a candidate modulator of morphine CPP through a GABAA1-related VTA Ca2 +-CaMK-cAMP-CREB mechanism and support RVG29 liposomes as an exploratory delivery strategy.