Synchronous development of spontaneous and evoked calcium-dependent properties in hypothalamic neurons.
The development of various related parameters was compared in hypothalamic neurons grown in primary culture. We measured: (i) low- and high-voltage-activated calcium currents; (ii) spontaneous and N-methyl-D-aspartate (NMDA)-induced fluctuations of intracellular calcium concentration; (iii) basal and NMDA- or potassium-evoked somatostatin release. Spontaneous calcium fluctuations appeared after 5 days in culture and increased progressively in amplitude and frequency over the next 8 days studied. Basal release of somatostatin was not detectable in 3 day-old cultures and reached a plateau at day 5. Responses evoked by exogenous stimulations (voltage-activated calcium currents, agonist-induced intracellular calcium rise and somatostatin release) appeared early in culture, increased in amplitude during 7-10 days and then stabilized. We conclude that, in hypothalamic neurons, the main neuronal functions develop in synchrony over a limited period of time.
Desarménien
M G
MG
Laboratoire de Neurobiologie Endocrinologique, URA 1197 CNRS, Université Montpellier II, France.
Devic
E
E
Rage
F
F
Dayanithi
G
G
Tapia-Arancibia
L
L
Richard
P
P
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004594:Electrophysiology; D007031:Hypothalamus / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D008564:Membrane Potentials / Q000502:physiology; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects; D013004:Somatostatin / Q000378:metabolism
D015220:Calcium Channels; D016194:Receptors, N-Methyl-D-Aspartate; D013004:Somatostatin; D016202:N-Methylaspartate; D011188:Potassium; D002118:Calcium