In vitro development of P- and R-like calcium currents in insect (Periplaneta americana) embryonic brain neurons.
Voltage-gated calcium currents are important for the survival and growth of embryonic cockroach brain neurons in primary culture. In the present experiments, we have studied, using the patch-clamp technique, the evolution with time in culture of the voltage-dependency and of the pharmacological properties of the calcium conductance of these neurons during the formation of a network. We have observed a progressive increase of the high-voltage-activated calcium conductance and a 10mV shift of the voltage-dependency of activation towards more negative potentials. The proportion of the R-like calcium current component increased during network formation. At the same time, the highly omega-AgaTxIVA-sensitive P-like component of the current is progressively replaced by a component which is less sensitive to the toxin. The origin and functional implications of these modifications are discussed.
Benquet
Pascal
P
UMR 6026, Campus de Beaulieu, Bt 13, Université de Rennes 1, 35042 Rennes Cedex, France. pbenquet@univ-rennes1.fr
Pichon
Yves
Y
Tiaho
François
F
D000818:Animals; D001921:Brain / Q000166:cytology / Q000196:embryology / Q000502:physiology*; D020865:Calcium Channels, P-Type / Q000502:physiology*; D020908:Calcium Channels, R-Type / Q000502:physiology*; D002478:Cells, Cultured; D015640:Ion Channel Gating; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010526:Periplaneta
D020865:Calcium Channels, P-Type; D020908:Calcium Channels, R-Type