Aims: 

Neuronal migration is a process in which neuron – glial cell interactions play a major role. In previous studies we described the ability of embryonic peripheral neurons to migrate in association with glial cells to form cellular aggregates. These results point to a key role of glia in the formation of neural cell networks. The purpose of this study was to characterize the effects of extracellular application of purinergic nucleosides and nucleotides on calcium signaling and their role in the regulation of the cell – complex migration.

Methods: 

We used 1) Fura – 2 calcium to quantify calcium signals induced by extracellular application of 1 mM ATP and NAADP and 10 mM adenosine in dissociated E7 chick ciliary ganglion cells; 2) time – lapse experiments and quantitative analysis of cell trajectories to compare the velocity of migration in the above different conditions.

Results: 

Adenosine, ATP and NAADP, when given extracellularly, directly activated a calcium response in both neurons and glia with different and independent mechanisms. Adenosine and NAADP strongly decreased the modulus of the velocity of the neuron – glial cell complex whereas no differences were observed in the presence of ATP. (CTR: v = 1.48 ± 0.06 mm/min, n = 24; ATP: v = 1.47 ± 0.06 mm/min, n = 8; NAADP: v = 1.02 ± 0.04 mm/min, n = 10; Ado v = 1.9 ± 0.04 mm/min, n = 20).

Conclusions: 

These results provide evidence for a role of nucleoside and nucleotide signaling in the regulation of cellular migration in developing peripheral ganglion cells. Whether NAADP acts on intracellular Ca²⁺– channels or on plasma membrane receptors remains to be established.