title: Hippocampal acetylcholine depletion has no effect on anxiety, spatial novelty preference, or differential reward for low rates of responding (DRL) performance in rats.
abstract: We investigated the role of the septo-hippocampal cholinergic projection in anxiety, spatial novelty preference, and differential reward for low rates of responding (DRL) performance. Cholinergic neurons of the rat medial septum (MS) and the vertical limb of the diagonal band of Broca (VDB) were lesioned using the selective immunotoxin, 192 IgG-saporin. Rats were then tested on several behavioral tests previously shown to be sensitive to either (a) hippocampal lesions or (b) nonselective MS/VDB lesions which target both cholinergic and γ-aminobutyric acid (GABA)-ergic projections, or both. Saporin lesions substantially reduced hippocampal cholinergic innervation, resulting in an absence of acetyl cholinesterase staining and markedly reduced choline acetyltransferase activity (mean reduction: 80 ± 5%; range: 50-97%). However, the saporin-lesioned rats did not differ from control rats in any of the behavioral tests. Thus we found no evidence from these lesion studies that the septo-hippocampal cholinergic projection plays an essential role in anxiety, spatial novelty preference, or DRL.
authors.affiliation: University of Oxford.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: McHugh
authors.affiliation: University of Oxford.
authors.forename: Anna
authors.initials: A
authors.lastname: Francis
authors.affiliation: Michigan State University.
authors.forename: J Devin
authors.initials: JD
authors.lastname: McAuley
authors.affiliation: Bowling Green State University.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Stewart
authors.affiliation: University of Oxford.
authors.forename: Mark G
authors.initials: MG
authors.lastname: Baxter
authors.affiliation: University of Oxford.
authors.forename: David M
authors.initials: DM
authors.lastname: Bannerman
mesh_terms: D000109:Acetylcholine / Q000378:metabolism / Q000502:physiology*; D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D001007:Anxiety / Q000503:physiopathology*; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D059329:Cholinergic Neurons / Q000187:drug effects / Q000502:physiology; D020667:Diagonal Band of Broca / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D005106:Exploratory Behavior / Q000502:physiology*; D006624:Hippocampus / Q000737:chemistry / Q000201:enzymology / Q000502:physiology*; D008297:Male; D009043:Motor Activity; D009434:Neural Pathways / Q000502:physiology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D012201:Reward; D054789:Ribosome Inactivating Proteins, Type 1 / Q000494:pharmacology; D000076985:Saporins; D012686:Septal Nuclei / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
chemical_list: D011500:Protein Synthesis Inhibitors; D054789:Ribosome Inactivating Proteins, Type 1; D002795:Choline O-Acetyltransferase; D000110:Acetylcholinesterase; D000076985:Saporins; D000109:Acetylcholine