Issue Cover (June 2018)

Front cover:Background: The indirect pathway striatal medium spiny projection neurons (iMSNs) are critical to motor and cognitive brain functions. These neurons express a high level of cAMP‐increasing adenosine A2a receptors (A2aRs). Main findings: In this study, we used chemogenetic techniques to mimic adenosine A2a receptor activation and to increase cAMP production selectively in indirect pathway iMSNs, while monitoring their spike firing in freely moving mice. We show that cAMP‐producing chemogenetic activation increases the spike firing in indirect pathway iMSNs, leading to an inhibition of globus pallidus external segment (GPe) neuron spike firing and an excitation of a subgroup of neurons in the subthalamic nucleus (STN). Implication: Taken together, our results strongly suggest that cAMP production in iMSNs can increase iMSN spiking activity and cause motor inhibition, thus addressing a long‐standing question about the cellular functions of the cAMP‐producing A2aRs in iMSNs. Image content: Green: green fluorescent protein labels gamma amino butyric acid (GABA). Red: stain for tyrosine hydroxylase labels dopamine neurons in the substantia nigra and their projection to the striatum.Read the full article ‘Cyclic AMP‐producing chemogenetic activation of indirect pathway striatal projection neurons and the downstream effects on the globus pallidus and subthalamic nucleus in freely moving mice’ by S. Bouabid, F‐M. Zhou ( J. Neurochem . 2018, vol. 145 (6), pp. 436–448) on doi: 10.1111/jnc.14331