Calcium channels coupled to glutamate release identified by omega-Aga-IVA.
Presynaptic calcium channels are crucial elements of neuronal excitation-secretion coupling. In mammalian brain, they have been difficult to characterize because most presynaptic terminals are too small to probe with electrodes, and available pharmacological tools such as dihydropyridines and omega-conotoxin are largely ineffective. Subsecond measurements of synaptosomal glutamate release have now been used to assess presynaptic calcium channel activity in order to study the action of peptide toxins from the venom of the funnel web spider Agelenopsis aperta, which is known to inhibit dihydropyridine and omega-conotoxin-resistant neuronal calcium currents. A presynaptic calcium channel important in glutamate release is shown to be omega-Aga-IVA sensitive and omega-conotoxin resistant.
Department of Physiology, Tufts University School of Medicine, Boston, MA 02111.
T J
TJ
Turner
M E
ME
Adams
K
K
Dunlap
D060848:Agatoxins; D000818:Animals; D001496:Batrachotoxins / Q000494:pharmacology; D001921:Brain / Q000502:physiology / Q000648:ultrastructure; D002118:Calcium / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology*; D004533:Egtazic Acid / Q000494:pharmacology; D005625:Frontal Lobe / Q000648:ultrastructure; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D007700:Kinetics; D008978:Mollusk Venoms / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D013111:Spider Venoms / Q000494:pharmacology*; D013574:Synaptosomes / Q000502:physiology; D020867:omega-Agatoxin IVA; D020866:omega-Conotoxin GVIA
D060848:Agatoxins; D001496:Batrachotoxins; D015220:Calcium Channels; D005971:Glutamates; D008978:Mollusk Venoms; D013111:Spider Venoms; D020867:omega-Agatoxin IVA; C070132:omega-agatoxin III; D018698:Glutamic Acid; D004533:Egtazic Acid; D011189:Potassium Chloride; D020866:omega-Conotoxin GVIA; D002118:Calcium