Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.06.25.172585v1?rss=1 Authors: Godfrey, N., Borgland, S. L. Abstract: Dopamine neurons in the ventral tegmental area (VTA) are important for energizing goal directed behaviour towards food and are sensitive to changes in metabolic states. Fasting increases the incentive motivation for food, mobilization of energy stores and have sex-dependent effects. However, it is unknown how acute fasting alters excitatory or inhibitory synaptic transmission onto VTA dopamine neurons. An acute 16h overnight fast induced increased food seeking behaviour that was more predominant in male mice. Fasting increased miniature excitatory postsynaptic current (mEPSC) frequency and amplitude in male, but not female mice. This effect was not due to altered release probability as there was no change in the paired pulse ratio, nor was it due to an altered postsynaptic response as there was no change in the AMPAR/NMDA ratio or response to glutamate uncaging. However, this effect was consistent with an increase in the number of release sites. In addition, depolarization-induced-suppression of excitation (DSE), a measure of short-term endocannabinoid-mediated plasticity, was enhanced in female but not male fasted mice. There were no fasting-induced changes at inhibitory synapses onto dopamine neurons of male or female mice. Taken together, these results demonstrate that fasting influences excitatory synapses differentially in male and female mice, but preserves inhibitory synapses onto dopamine neurons, indicating that the mesolimbic circuit of male and female mice respond differently to acute energy deprivation. Copy rights belong to original authors. Visit the link for more info