title: Calcium channel types involved in intrinsic amino acid neurotransmitters release evoked by depolarizing agents in cortical neurons.
abstract: Although numerous biochemical and electrophysiological studies have already established many of the properties of the putative Ca2+ receptor for exocytosis at the synapse, the molecular mechanism that involves the influx of Ca2+ and the release of neurotransmitters has remained elusive. Several relationships have been established between neurotransmitter release and Ca2+ channel involved, but no work attempting to connect a particular neurotransmitter release, the effector which produces the release and the opening of a Ca2+ channel type has been performed. This work shows, data dealing with this subject. Based on our results, we have reached the following conclusions: (1) Ca2+ channel types P/Q, N and L mediate Ca2+ entry evoked by high KCl and veratridine, and P/Q and N but not L-type Ca2+ channels are involved when the effector is 4-aminopyridine (4-AP); (2) When we compare the relationship between the amino acid release and the Ca2+ channels which are opened by different depolarizing agents, we find that the release of a particular amino acid neurotransmitter not only depends on the opening of the voltage-dependent Ca2+ channel but also on the effector which produces the opening; and (3) the amount of amino acid release evoked by the different depolarizing agents is not correlated with the elevation of intracellular Ca2+ produced by them. From all of these results, we may conclude that calcium concentration in the active zone is not the only important factor in mediating amino acid release.
authors.affiliation: Facultad de Farmacia, Instituto de Bioquímica, Centro mixto CSIC-UCM, 28040, Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: López
authors.forename: M J
authors.initials: MJ
authors.lastname: Oset-Gasque
authors.forename: S
authors.initials: S
authors.lastname: Figueroa
authors.forename: J J
authors.initials: JJ
authors.lastname: Albarrán
authors.forename: M P
authors.initials: MP
authors.lastname: González
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism*; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D005260:Female; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D014701:Veratridine / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009467:Neuromuscular Depolarizing Agents; D018377:Neurotransmitter Agents; D011189:Potassium Chloride; D014701:Veratridine; D015761:4-Aminopyridine; D002118:Calcium