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 chara cterization of two alpha Bgtx receptor subtypes, alpha 7 and alpha 7-a lpha 8 from chick optic lobe (COL). In order to study whether other al pha 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 hat ching (D1). In chick retina, an alpha 8 subtype representing 50% of al l 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.