CORRELATIONS BETWEEN CHOLINERGIC NEURONS AND MUSCARINIC M2 RECEPTORS IN THE RAT RETINA

ACETYLCHOLINE is well established as the neurotransmitter of starburst amacrine cells in the vertebrate retina but their function is poorly understood. We compared the distribution of muscarinic m2 receptors in the rat retina with the localization of the starburst cell processes. mAChR2 immunoreactivity appeared in a central band in the inner plexi form layer, which did not co-localize with the processes of the cholin ergic amacrine cells. We found co-labelling of VAChT and ChAT making i t highly unlikely that there are undetected cholinergic neurons in rat retina. Most mAChR2 receptors were located far from the cholinergic n eurons, suggesting that most of them are unlikely to be associated wit h conventional cholinergic synapses. (C) 1998 Rapid Science Ltd.