The intracellular free Ca²⁺ concentration ([Ca²⁺]_i) was measured in isolated neurocytes prepared from Sprague-Dawley rats with Fura-2 double-wavelength fluoremetry. The results showed that the [Ca²⁺]_i, of the resting neurocytes in Ca²⁺-containing solution was 109±12nmol/L(x±s, n=9).KCl (30mmol/L) markedly evoked [Ca²⁺] of the neurocytes (P＜0.01, n=9),and the rises of [Ca²⁺]_i by KCl is a concentration-dependent response.These results suggest that the adoption of Fura-2 double-wavelength fluoremetry in dissociated rat neurocytes in a useful and relatively easily applicable technique for monitoring intracellular Ca²⁺ changes.