The developing chick brain shows a dramatic increase in the omega-conotoxin binding sites around the hatching period.
omega-Conotoxin CVIA, a 27 amino acid neuropeptide toxin believed to target voltage sensitive calcium channels (Cruz et al., 1987, Biochemistry 26 (3), 820-824) was bound to developing chick brain at embryonic day 9-post hatch day 10. A two-fold increase was observed in omega-Conotoxin binding sites around chick hatching, embryonic days 18-20. Depolarization induced 45Ca fluxes also increased around hatching. omega-Conotoxins block > or = 80% of these 45Ca fluxes throughout development. Competition binding did not detect large differences in the binding affinity of sites during development. We conclude from these data that the increases in omega-Conotoxin binding sites and 45Ca fluxes around chick hatching are related to one of the presynaptic mechanisms of neuronal maturation necessary for normal neuronal function and chick behavior after hatching.
Azimi-Zonooz
A
A
Department of Biology, University of Utah, Salt Lake City 84112.
Litzinger
M J
MJ
D000818:Animals; D001921:Brain / Q000254:growth & development*; D001923:Brain Chemistry / Q000187:drug effects*; D002121:Calcium Channel Blockers / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002642:Chick Embryo; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010456:Peptides, Cyclic / Q000378:metabolism*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002132:Calcium Radioisotopes; D007457:Iodine Radioisotopes; D009419:Nerve Tissue Proteins; D010456:Peptides, Cyclic; D020960:omega-Conotoxins; C053423:Conus magus toxin