Differential localization of acetylcholinesterase in relation to pre- and postsynaptic nicotinic receptors in the chick brain

Immunofluorescence and confocal microscopy were combined to study the distr ibution of acetylcholinesterase in relation to the localization of the beta 2 subunit of the nicotinic acetylcholine receptors in the chick brain. In s everal areas where the beta2 subunit is recognizably part of presynaptic re ceptors, the localization of acetylcholinesterase appeared not to overlap t he localization of beta2. On the other hand, acetylcholinesterase and the b eta2 subunit exhibited a strictly matching localization in areas where post synaptic nicotinic receptors are known to be present. These data may repres ent a morphological substrate for possible differential actions of acetylch olinesterase at presynaptic and postsynaptic nicotinic sites. (C) 2001 Else vier Science B.V. All rights reserved.