Table 3.

Changes in spontaneous calcium transients produced by chronic glutamate antagonist treatments for the first 3 d in culture do not correlate with the sprouting effects of the same treatment

Number of cells7777607467
% of cells active4882635867
% with waves only 8 3262113
% with spikes only7881425873
% with spikes and waves1416322114
% with small response only8476847273
% with a large response1624162827
Average number of waves per active cell0.19  ± 0.080.25  ± 0.080.66  ± 0.100.45  ± 0.090.23  ± 0.08
Average number of spikes per active cell2.30  ± 0.253.43  ± 0.261.71  ± 0.261.39  ± 0.182.24  ± 0.29
  • Sister cultures of tectal neurons were grown in normal media and supplemented with glutamate receptor antagonists as shown. Calcium transients were recorded for fields of cells every 30 sec for 30 min; the number and type of observed calcium changes were quantitated for each cell, and then the average response for all neurons in the field was calculated. Antagonists that produce an increased number of free neurite ends among contacted tectal neurons cannot be distinguished from treatments that do not increase free neurite ends in terms of their effects on calcium transients.