Figure 5.

External calcium requirements for endogenous amino acid release from acute cortical slices. A) Release of endogenous d-serine from perfused cortical slices by 50 μM veratridine in the presence of 2.5 mM CaCl₂ (•) or 0.2 mM EGTA instead of CaCl₂ (Ca²⁺-free) (○). B) Maximal endogenous d-serine release promoted by veratridine in the presence and absence of Ca²⁺. C) Release of endogenous l-serine from cortical slices by 50 μM veratridine is independent of external Ca²⁺. D) Maximal endogenous l-serine release promoted by veratridine in the presence and absence of Ca²⁺. E) Release of endogenous l-glutamate from cortical slices by 50 μM veratridine is decreased by removal of external Ca²⁺. F) Maximal endogenous l-glutamate release promoted by veratridine in the presence and absence of Ca²⁺. Results represent average ± se of 5 experiments with different slice preparations done in triplicates. ***P < 0.001 vs. control.