Table 1.

Effect of serum on neurotrophin-induced synaptic connections among E16 hippocampal neurons

	% Connected afferents
	Serum-containing medium	Serum-free medium
Control	12.2  ± 6.3 (n = 19 cells)	4.8  ± 5.7 (n = 7 cells)
NT-3	58.5  ± 9.3 (n = 9 cells)**	76.9  ± 8.7 (n = 9 cells)***
BDNF	64.6  ± 8.8 (n = 21 cells)**	80.6  ± 7.9 (n = 9 cells)***

E16 hippocampal cells were grown for 14 d in serum-containing medium or initially in serum-containing medium and from day 10 to day 14 in serum-free medium. NT-3 or BDNF were added in both cases from day 11 to day 14 when recordings were done. Results are the mean ± SEM of connection ratios per cell. **p< 0.002; ***p < 0.001, t test.