Co-expression of α7 and β2 nicotinic acetylcholine receptor subunit mRNAs within rat brain cholinergic neurons

• Published in: Neuroscience Vol. 119; no. 4; pp. 965 - 977
• Main Authors: Azam, L, Winzer-Serhan, U, Leslie, F.M
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-07-2003; Elsevier
• Subjects: basal forebrain; Biological and medical sciences; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; choline acetyltransferase; digoxygenin; Fundamental and applied biological sciences. Psychology; glutamic acid decarboxylase; mesopontine tegmentum; non-radioactive in situ hybridization; Vertebrates: nervous system and sense organs; MSDB; non-radioactive in situ hybridization; ACh; HDB; UTP; VDB; nAChR; ChAT; Dig; OT; mesopontine tegmentum; digoxygenin; EEG; MS; basal forebrain; LDTg; AL; GAD; CP; glutamic acid decarboxylase; NAC-c; choline acetyltransferase; NB; PPTg; REM; NAC-s; Cholinergic neuron; Cholinergic receptor; Vertebrata; Mammalia; Rat; Rodentia; Central nervous system; Gene expression; Subunit; Nicotinic receptor; Brain (vertebrata)
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/S0306-4522(03)00220-3

Nicotine enhances cognitive and attentional processes through stimulation of the basal forebrain cholinergic system. Although muscarinic cholinergic autoreceptors have been well characterized, pharmacological characterization of nicotinic autoreceptors has proven more difficult. The present study used double-labeling
in situ hybridization to determine expression of nicotinic acetylcholine receptor (nAChR) subunit mRNAs within basal forebrain cholinergic neurons in order to gain information about possible nAChR autoreceptor properties. Cholinergic cells of the mesopontine tegmentum and striatal interneurons were also examined, as were septohippocampal GABAergic neurons that interact with cholinergic neurons to regulate hippocampal activity. α7 and β2 nAChR mRNAs were found to be co-expressed in almost all cholinergic cells and in the majority of GABAergic neurons examined. α4 nAChR mRNA expression was restricted to cholinergic cells of the nucleus basalis magnocellularis, and to non-cholinergic cells of the medial septum and mesopontine tegmentum.
These data suggest possible regional differences in the pharmacological properties of nicotinic autoreceptors on cholinergic cells. Whereas most cholinergic cells express rapidly desensitizing α7 homomers or α7β2 heteromers, cortical projection neurons may also express a pharmacologically distinct α4β2 nAChR subtype. There may also be differential nAChR regulation of cholinergic and non-cholinergic cells within the mesopontine tegmentum that are implicated in acquisition of nicotine self-administration.