Expression of alpha-bungarotoxin receptor subtypes in chick central nervous system during development.

Chick central nervous system (CNS) expresses alpha-bungarotoxin (alpha Bgtx) receptors. We have recently reported the purification and characterization of two alpha Bgtx receptor subtypes, alpha 7 and alpha 7-alpha 8 from chick optic lobe (COL). In order to study whether other alpha Bgtx receptor subtypes are present in other areas of the chick CNS, as well as their developmental expression, we used anti-alpha 7 and anti-alpha 8 subunit-specific antibodies to study alpha Bgtx receptors at different developmental stages in COL, brain and retina. We found that only the alpha 7 and alpha 7-alpha 8 subtypes are present at all developmental stages in chick COL and brain, where they represent 90% of all the alpha Bgtx receptors at embryonic day 19 and 1 day post hatching (D1). In chick retina, an alpha 8 subtype representing 50% of all alpha Bgtx receptors at D1 is present in addition to the alpha 7 and alpha 7-alpha 8 subtypes, and the expression of this alpha 8 subtype increases during neurodevelopment.