Opioid withdrawal abruptly disrupts amygdala circuit function by reducing peptide actions

Abstract

SummaryOpioid withdrawal drives relapse and contributes to compulsive drug use through disruption of endogenous opioid dependent learning circuits in the amygdala. Normally, endogenous opioids control these circuits by inhibiting glutamate release from basolateral amygdala principal neurons onto GABAergic intercalated cells. Using patch-clamp electrophysiology in rat brain slices, we reveal that opioid withdrawal dials down this endogenous opioid inhibition of synaptic transmission. Peptide activity is dialled down due to a protein kinase A dependent increase in the activity of the peptidase, neprilysin. This disrupts peptidergic control of both GABAergic and glutamatergic transmission through multiple amygdala circuits, including reward-related outputs to the nucleus accumbens. This likely disrupts peptide-dependent learning processes in the amygdala during withdrawal. and may direct behaviour towards compulsive drug use. Restoration of endogenous peptide activity during withdrawal may be a viable option to normalise synaptic transmission in the amygdala and restore normal reward learning.In BriefWe find that opioid withdrawal dials down inhibitory neuropeptide activity in the amygdala. This disrupts both GABAergic and glutamatergic transmission through amygdala circuits, including reward-related outputs to the nucleus accumbens. This likely disrupts peptide-dependent learning processes in the amygdala during withdrawal and may direct behaviour towards compulsive drug use.HighlightsDuring opioid withdrawal, peptidase activity is upregulated in an amygdala circuitPeptidase upregulation occurs via a PKA-dependent mechanismIncreased peptidase activity limits peptidergic control of synaptic transmissionOpioid withdrawal disrupts the balance of excitation and inhibition in the amygdala