Title: Klaus Ballanyi, University of Alberta
Start date: Jun 29 2018
Start time: 11:15 am
End time: 12:15 pm
Location: Max Planck House Lecture Hall

Locus coeruleus (LC) neurons innervate most brain areas to control various behaviors like arousal, memory, pain sensation, anxiety and opioid (withdrawal) effects. The neonatal LC is an established model network for gap junction-mediated spike synchronization. We found instead in rat brain slices that the neonatal LC generates at ~1 Hz about 0.2 s-lasting extracellular discharge bursts comprising summated non-synchronous phase-locked and jittered spiking. We now report that the bell-shaped pattern of this rhythm is transformed into (i) multi-peak bursting by m-opioid or a2 receptors, (ii) ramp-like bursting by glutamate or quisqualate, (iii) spindle-like oscillations by kainate or AMPA, (iv) 3-10 s-lasting bursts by NMDA. During these patterns, LC neurons depolarize and discharge either tonically, in bursts or with spike amplitude oscillations. NMDA bursting is reversed with APV and the other patterns with kynurenic acid. Control rhythm persists in kynurenic acid, APV and CNQX with an accelerating effect of the latter two agents. The excitatory CNQX action is mediated by a 'TARP' auxiliary AMPA receptor subunit. Astrocytes accelerate the RFP when noradrenaline within the LC activates their a1 receptor to cause vesicular release of lactate which then excites LC neurons. Our findings indicate that dynamic connectivity changes enable the neonatal LC to generate multiple output patterns that may finetune its influence on multiple brain functions.

Host: Oxana Eschnko