Linked Life Data

9336768

Source:http://linkedlifedata.com/resource/pubmed/id/9336768

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1997-11-26
pubmed:abstractText
The effect of cyclic adenosine 3',5'-monophosphate (cAMP) on epileptiform activity in rat hippocampal slices was investigated. Bath-applied cAMP reversibly decreased the frequency of extracellularly recorded discharges in the CA3 subfield induced by bethanechol- or theophylline-containing solutions. Because cAMP was presumed to be relatively membrane impermeant, we developed and tested the hypothesis that this cAMP-mediated effect occurred extracellularly through the catabolic conversion of cAMP to 5'-AMP and, in turn, to adenosine, a known inhibitory neuromodulator. Three predictions derived from this catabolic hypothesis were tested. First, blockers of the enzymes involved were predicted to antagonize this effect of cAMP. In contrast, the coapplication of a cAMP-phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX), or a 5'-nucleotidase inhibitor, adenosine 5'-[alpha, beta-methylene] diphosphate (AMP-CP), enhanced the cAMP-induced suppressive effect. Second, the nonhydrolyzable cAMP analogs, dibutyryl- and 8-bromo-cAMP, were predicted to be ineffective. Low concentrations (5-40 microM) of these two derivatives, however, also suppressed bethanechol-induced discharges, while, at a higher concentration (100 microM), both analogs increased discharge frequencies. Third, enzymatic catabolism of adenosine was predicted to antagonize cAMP's effect, but coapplying adenosine deaminase (10 U/mL) did not diminish this action. Because these data did not support the catabolic hypothesis, other, as yet undefined, mechanisms must be responsible for the discharge-suppressant effect of cAMP.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1044-7393
pubmed:author
pubmed:issnType
Print
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
265-78
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Suppression of drug-induced epileptiform discharges by cyclic AMP in rat hippocampus.
pubmed:affiliation
Neurotoxicology Branch, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5425, USA. Dr._James_Apland@ftdetrck-ccmail.army.mil
pubmed:publicationType
Journal Article