Distinct eLPB projections for methamphetamine withdrawal anxiety and primed reinstatement of conditioned place preference.

Methamphetamine (METH) withdrawal anxiety symptom and relapse have been significant challenges for clinical practice, however, the underlying neuronal basis remains unclear. Our recent research has identified a specific subpopulation of choline acetyltransferase (ChAT) neurons localized in the external lateral portion of parabrachial nucleus (eLPB), which modulates METH primed-reinstatement of conditioned place preference (CPP). Here, the anatomical structures and functional roles of eLPB projections in METH withdrawal anxiety and primed reinstatement were further explored. In the present study, a multifaceted approach was employed to dissect the LPB projections in male mice, including anterograde and retrograde tracing, acetylcholine (Ach) indicator combined with fiber photometry recording, photogenetic and chemogenetic regulation, as well as electrophysiological recording. METH withdrawal anxiety-like behaviors and METH-primed reinstatement of conditioned place preference (CPP) were assessed in male mice. We identified that eLPB send projections to PKCδ-positive (PKCδ) neurons in lateral portion of central nucleus of amygdala (lCeA) and oval portion of bed nucleus of the stria terminalis (ovBNST), forming eLPB-lCeA and eLPB-ovBNST pathways. At least in part, the eLPB neurons positively innervate lCeA neurons and ovBNST neurons through regulating synaptic elements of presynaptic Ach release and postsynaptic nicotinic acetylcholine receptors (nAChRs). METH withdrawal anxiety and METH-primed reinstatement of CPP respectively recruit eLPB-lCeA pathway and eLPB-ovBNST pathway in male mice. Our findings put new insights into the complex neural networks, especially focusing on the eLPB projections. The eLPB is a critical node in the neural networks governing METH withdrawal anxiety and primed-reinstatement of CPP through its projections to the lCeA and ovBNST, respectively.