Linked Life Data

9125435

Source:http://linkedlifedata.com/resource/pubmed/id/9125435

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1997-7-17
pubmed:abstractText
The initiation of focal interictal epileptiform activity (FIEA) has been shown to depend on the activation of a sufficiently large volume of brain tissue. We estimated the size of this 'critical volume' for the convulsant pentylenetetrazol (PTZ) by analyzing the diffusion following its microinjection into rat motor cortex. PTZ concentration was monitored 100-200 microm away from the injection site with a PTZ-sensitive microelectrode. Diffusion analysis in 0.3% agar yielded the free diffusion coefficient D (8.50 +/- 0.15 X 10(-6) cm2 x s(-1) at 37 degrees C, median +/- S.E.M.). In brain tissue, diffusion was modified by extracellular volume fraction (alpha), tortuosity (lambda = (D/ADC)1/2; ADC = apparent diffusion coefficient) and non-specific uptake (k'). Using a value of 0.2 for alpha from previous studies, we found values of lambda = 1.61 +/- 0.01, k' = 3.37 +/- 0.15 X 10(-3) s(-1) and an injected volume U of 5.16 +/- 0.45 X 10(-10) l for pulses without FIEA, and lambda = 1.95 +/- 0.06, k' = 6.24 +/- 1.73 X 10(-3) s(-1) and U = 7.40 +/- 0.66 X 10(-10) l for pulses with FIEA. From the calculated concentration distribution of PTZ during FIEA we estimated a threshold concentration of about 1.77 mM PTZ and a volume with a radius of about 219 microm in which this concentration had to be exceeded. Since this critical volume was comparable in size to foci elicited by penicillin or electric stimuli in previous studies, it is concluded that it is determined by intrinsic tissue properties rather than by the convulsive agent being used.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
753
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
86-97
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Critical volume of rat cortex and extracellular threshold concentration for a pentylenetetrazol-induced epileptic focus.
pubmed:affiliation
Institut für Physiologie der Universität Münster, Germany.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.