Linked Life Data

2215927

Source:http://linkedlifedata.com/resource/pubmed/id/2215927

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1990-11-15
pubmed:abstractText
Changes in extracellular levels of acetylcholine and choline in the hippocampal formation were measured using intracerebral microdialysis coupled to high performance liquid chromatography with post-column enzyme reaction and electrochemical detection. Various pharmacological and physiological manipulations were applied to awake unrestrained normal rats and rats subjected to a cholinergic denervation of the hippocampus by a complete fimbria-fornix lesion (1-2 weeks previously). Low baseline levels of acetylcholine (about 0.3 pmol/15 min sample) could be detected in the absence of acetylcholinesterase inhibition in all animals. However, in order to obtain stable and more readily detectable levels, the acetylcholinesterase inhibitor neostigmine was added to the perfusion medium at a concentration of 5 or 10 microM and was used during all subsequent manipulations. Addition of neostigmine increased acetylcholine levels approximately 10-fold (to 3.7 pmol 15 min) in the normal rats, which was about 4-fold higher than the levels recovered from the denervated hippocampi. Depolarization by adding KCl (100 mM) to the perfusion fluid produced a 3-fold increase in the extracellular acetylcholine levels, and the muscarinic antagonist atropine (3 microM) resulted in a 4-fold increase in the normal rats, whereas these drugs induced only small responses in the denervated rats. Neuronal impulse blockade by tetrodotoxin (1 microM) resulted, in normal rats, in a 70% reduction in extracellular acetylcholine levels. Sensory stimulation by handling increased acetylcholine levels by 94% in the normal rats, whereas this response was almost totally abolished in the denervated hippocampi. Behavioural activation by electrical stimulation of the lateral habenula resulted in a 4-fold increase in acetylcholine release in normal animals, and this response was totally blocked by a transection of the lateral habenular efferents running in the fasciculus retroflexus. The levels obtained by lateral habenula stimulation were reduced by about 95% in the rats with fimbria-fornix lesions. Following an acute knife transection of the fimbria-fornix performed during ongoing dialysis, acetylcholine levels dropped instantaneously by 70%, indicating that the extracellular acetylcholine levels in the hippocampus are maintained by a tonic impulse flow in the septohippocampal pathway. The extracellular levels of choline were reduced by about 30% after the addition of neostigmine in the normal rats, and increased by about 50% in both normal and denervated rats after addition of KCl to the perfusion fluid. No changes could be detected after atropine, handling, lateral habenula stimulation, or acute fimbria-fornix or fasciculus retroflexus transection.(ABSTRACT TRUNCATED AT 400 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0306-4522
pubmed:author
pubmed:issnType
Print
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
325-38
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:2215927-Acetylcholine, pubmed-meshheading:2215927-Animals, pubmed-meshheading:2215927-Axons, pubmed-meshheading:2215927-Behavior, Animal, pubmed-meshheading:2215927-Choline, pubmed-meshheading:2215927-Cholinesterase Inhibitors, pubmed-meshheading:2215927-Chromatography, High Pressure Liquid, pubmed-meshheading:2215927-Dialysis, pubmed-meshheading:2215927-Electric Stimulation, pubmed-meshheading:2215927-Electrodes, Implanted, pubmed-meshheading:2215927-Handling (Psychology), pubmed-meshheading:2215927-Hippocampus, pubmed-meshheading:2215927-Histocytochemistry, pubmed-meshheading:2215927-Male, pubmed-meshheading:2215927-Neostigmine, pubmed-meshheading:2215927-Potassium Chloride, pubmed-meshheading:2215927-Rats, pubmed-meshheading:2215927-Rats, Inbred Strains, pubmed-meshheading:2215927-Tetrodotoxin
pubmed:year
1990
pubmed:articleTitle
Acetylcholine release in the rat hippocampus as studied by microdialysis is dependent on axonal impulse flow and increases during behavioural activation.
pubmed:affiliation
Department of Medical Cell Research, Section of Neurobiology, Lund, Sweden.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't