Induction of calcium-independent nitric oxide synthase activity in cultured cerebellar granule neurons.

Cultured cerebellar granule neurons were assayed for nitric oxide synthase (NOS) activity by measuring the conversion of L-arginine to L-citrulline. Granule neurons expressed constitutive NOS activity which was calcium-dependent. Treatment of neuron cultures for 24 h with the combined stimulation of IFN-gamma plus IL-1 beta, TNF-alpha and LPS induced NOS activity by 87-fold which was calcium-independent. We conclude that cultured cerebellar granule neurons can express both the constitutive and inducible forms of NOS activity.