Research Report Co-localization of PRiMA with acetylcholinesterase in cholinergic neurons of rat brain: An immunocytochemical study Zaineb Henderson a, ⁎ , Nazia Matto a , Danielle John a , Natalia N. Nalivaeva b , Anthony J. Turner b a Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK b Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK ARTICLE INFO ABSTRACT Article history: Accepted 6 May 2010 Available online 13 May 2010 In the central nervous system, acetylcholinesterase (AChE) is present in a tetrameric form that is anchored to membranes via a proline-rich membrane anchor (PRiMA). Previously it has been found that principal cholinergic neurons in the brain express high concentrations of AChE enzymic activity at their neuronal membranes. The aim of this study was to use immunocytochemical methods to determine the distribution of PRiMA in these neurons in the rat brain. Confocal laser and electron microscopic investigations showed that PRiMA immunoreactivity is associated with the membranes of the somata, dendrites and axons of cholinergic neurons in the basal forebrain, striatum and pedunculopontine nuclei, i.e. the neurons that innervate forebrain and brainstem structures. In these neurones, PRiMA also co- localizes with AChE immunoreactivity at the plasma membrane. PRiMA label was absent from neighboring GABAergic neurons, and from other neurons of the brain known to express high levels of AChE enzymic activity including cranial nerve motor neurons and dopaminergic neurons of the substantia nigra zona compacta. A strong association of AChE with PRiMA at the plasma membrane is therefore a feature specific to principal cholinergic neurons that innervate the central nervous system. © 2010 Elsevier B.V. All rights reserved. Keywords: PRiMA Acetylcholinesterase Immunocytochemistry Medial septum Nucleus basalis magnocellularis Pedunculopontine nucleus Cranial nerve nuclei Substantia nigra 1. Introduction Acetylcholinesterase (AChE) is a globular, glycosylated protein that lacks a transmembrane peptide-anchor region and occurs in several molecular forms, dependent upon alternative splicing of the AChE gene. There are soluble forms of AChE such as the “read through” AChE (Zimmerman and Soreq, 2006), and membrane-bound forms that associate with different types of transmembrane anchor (Massoulie et al., 2005). The most common transcript of AChE in the central BRAIN RESEARCH 1344 (2010) 34 – 42 ⁎ Corresponding author. Fax: + 44 113 3434228. E-mail address: z.henderson@leeds.ac.uk (Z. Henderson). URL: http://www.fbs.leeds.ac.uk/staff/profile.php?tag=Henderson_Z (Z. Henderson). Abbreviations: 3n, oculomotor nucleus; Aβ, amyloid beta peptide; AChE, acetylcholinesterase; ChAT, choline acetyltransferase; EM, electron microscope; ER, endoplasmic reticulum; GAD67, glutamic acid decarboxylase 67; LB, lamellar body; MS/DB, medial septum diagonal band area; nAChR, nicotinic acetylcholine receptor; NBM, nucleus basalis magnocellularis; PPN, pedunculopontine nucleus; PRiMA, proline-rich membrane anchor; SC, superior colliculus; SNc, substantia nigra zona compacta; TH, tyrosine hydroxylase 0006-8993/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.brainres.2010.05.022 available at www.sciencedirect.com www.elsevier.com/locate/brainres