Premium
Developmental regulation of T‐, N‐ and L‐type calcium currents in mouse embryonic sensory neurones
Author(s) -
Desmadryl G.,
Hilaire C.,
Vigues S.,
Diochot S.,
Valmier J.
Publication year - 1998
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.1998.00055.x
Subject(s) - dihydropyridine , voltage dependent calcium channel , calcium channel , patch clamp , nitrendipine , calcium , dorsal root ganglion , chemistry , medicine , endocrinology , biophysics , electrophysiology , neuroscience , biology , sensory system
We investigated the development of a low (T‐type) and two high voltage‐activated (N‐ and L‐type) calcium channel currents in large diameter dorsal root ganglion neurones acutely isolated from embryonic mice using the whole‐cell patch‐clamp technique. The low and high voltage‐activated barium currents (LVA and HVA) were identified by their distinct threshold of activation and their sensitivity to pharmacological agents, dihydropyridines and ω‐conotoxin‐GVIA, at embryonic day 13 (E13), E15 and E17–18, respectively, before, during and after synaptogenesis. The amplitude and density of LVA currents, measured during a –40 mV pulse from a holding potential of –100 mV, increased significantly between E13 and E15, and remained constant between E15 and E17–18. The density of global HVA current, elicited by 0 mV pulse, increased between E13 and E15/E17–18. The density of the N‐type current studied by the application of ω‐conotoxin‐GVIA (1 μ m ) increased significantly between E13 and E15/E17–18. The use of the dihydropyridine nitrendipine (1 μ m ) revealed that the density of L‐type current remained constant at each stage of development. Nevertheless, application of dihydropyridine Bay K 8644 (3 μ m ) demonstrated a significant slowing of the deactivation tail current between embryonic days 13 and 15, which may reflect a qualitative maturation of this class of calcium channel current. The temporal relationship between the changes in calcium channel pattern and the period of target innervation suggests possible roles of T‐, N‐ and L‐type currents during developmental key events such as natural neurone death and onset of synapse formation.