Calcium dynamics in gonadotropin-releasing hormone neurons

The gonadotropin-releasing hormone (GnRH) neurons represent the key output cells of the neuronal network controlling fertility. Intracellular calcium ion concentration ([Ca2+]i) is likely to be a key signaling tool used by GnRH neurons to regulate and co-ordinate multiple cell processes. This review examines the dynamics and control of [Ca2+]i in GT1 cells, embryonic GnRH neurons in the nasal placode culture, and adult GnRH neurons in the acute brain slice preparation. GnRH neurons at all stages of development display spontaneous [Ca2+]i transients driven, primarily, by their burst firing. However, the intracellular mechanisms generating [Ca2+]i transients, and the control of [Ca2+]i by neurotransmitters, varies markedly across the different developmental stages. The functional roles of [Ca2+]i transients are beginning to be unraveled with one key action being that of regulating the dynamics of GnRH neuron burst firing.