Autocrine Neuromodulation and Network Activity Patterns in the Locus Coeruleus of Newborn Rat Slices

Brain Sciences

Quinn Waselenchuk¹  Klaus Ballanyi¹ 

[1] Department of Physiology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada;

关键词: astrocytes;    brain slices;    calcium imaging;    calcium wave;    local field potential;    locus coeruleus;   

DOI  :  10.3390/brainsci12040437

来源: DOAJ

【 摘 要 】

Already in newborns, the locus coeruleus (LC) controls multiple brain functions and may have a complex organization as in adults. Our findings in newborn rat brain slices indicate that LC neurons (i) generate at ~1 Hz a ~0.3 s-lasting local field potential (LFP) comprising summated phase-locked single spike discharge, (ii) express intrinsic ‘pacemaker’ or ‘burster’ properties and (iii) receive solely excitatory or initially excitatory–secondary inhibitory inputs. μ-opioid or ɑ₂ noradrenaline receptor agonists block LFP rhythm at 100–250 nM whereas slightly lower doses transform its bell-shaped pattern into slower crescendo-shaped multipeak bursts. GABA_A and glycine receptors hyperpolarize LC neurons to abolish rhythm which remains though unaffected by blocking them. Rhythm persists also during ionotropic glutamate receptor (iGluR) inhibition whereas <10 mV depolarization during iGluR agonists accelerates spiking to cause subtype-specific fast (spindle-shaped) LFP oscillations. Similar modest neuronal depolarization causing a cytosolic Ca²⁺ rise occurs (without effect on neighboring astrocytes) during LFP acceleration by CNQX activating a TARP-AMPA-type iGluR complex. In contrast, noradrenaline lowers neuronal Ca²⁺ baseline via ɑ₂ receptors, but evokes an ɑ₁ receptor-mediated ‘concentric’ astrocytic Ca²⁺ wave. In summary, the neonatal LC has a complex (possibly modular) organization to enable discharge pattern transformations that might facilitate discrete actions on target circuits.

【 授权许可】

Unknown