An excitatory projection from ventromedial hypothalamus to lateral hypothalamus mediates stress-induced reinstatement of alprazolam-conditioned place preference in male mice.

Alprazolam (Alp) is a clinically common benzodiazepine (BZD) with a potential risk of abuse, yet the mechanisms underlying its reinstatement remain unclear. In this study, a conditioned place preference (CPP) paradigm combined with forced swim stress (FSS) was employed to induce CPP reinstatement in male mice with prior Alp exposure. The results demonstrated that the activity of CaMKIIα neurons in the ventromedial hypothalamus (VMH) was significantly increased following FSS-induced reinstatement of Alp-CPP. The lateral hypothalamus (LH) receives innervation from the VMH, and GABAergic neurons in the LH were activated during this process. Chemogenetic inhibition of VMHCaMKIIα-LH circuit significantly reduced FSS-induced reinstatement of Alp-CPP. Furthermore, chemogenetic activation of LH GABAergic neurons reversed the suppressive effects of inhibiting VMH CaMKIIα neurons projecting to the LH on Alp-CPP reinstatement. Collectively, these findings elucidate a critical role for the VMHCaMKIIα-LHGABA circuit in mediating stress-induced reinstatement of Alp-CPP in male mice, thereby advancing our understanding of the neural mechanisms underlying Alp reinstatement and providing novel insights for the prevention and treatment of BZD addiction.