Linked Life Data

12750065

Source:http://linkedlifedata.com/resource/pubmed/id/12750065

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-8-13
pubmed:abstractText
Intracellular pH (pHi) is an important modulator of cardiac function. The spatial regulation of pH within the cytoplasm depends, in part, on intracellular H+ (Hi+) mobility. The apparent diffusion coefficient for Hi+, DHapp, was estimated in single ventricular myocytes isolated from the rat, guinea pig, and rabbit. DHapp was derived by best-fitting predictions of a two-dimensional model of H+ diffusion to the local rise of intracellular [H+], recorded confocally (ratiometric seminaphthorhodafluor fluorescence) downstream from an acid-filled, whole cell patch pipette. Under CO2/HCO3--free conditions, DHapp was similar in all three species (mean values: 8-12.5 x 10-7 cm2/s) and was over 200-fold lower than that for H+ in water. In guinea pig myocytes, DHapp was increased 2.5-fold in the presence of CO2/HCO3- buffer, in agreement with previous observations in rabbit myocytes. Hi+ mobility is therefore low in cardiac cells, a feature that may predispose them to the generation of pHi gradients in response to sarcolemmal acid/base transport or local cytoplasmic acid production. Low Hi+ mobility most likely results from H+ shuttling among cytoplasmic mobile and fixed buffers. This hypothesis was explored by comparing the pHi dependence of intrinsic, intracellular buffering capacity, measured for all three species, and subdividing buffering into mobile and fixed fractions. The proportion of buffer that is mobile will be the main determinant of DHapp. At a given pHi, this proportion appeared to be similar in all three species, consistent with a common value for DHapp. Over the pHi range of 6.0-8.0, the proportion is expected to change, predicting that DHapp may display some pHi sensitivity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0363-6135
pubmed:author
pubmed:issnType
Print
pubmed:volume
285
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H1236-46
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Intracellular proton mobility and buffering power in cardiac ventricular myocytes from rat, rabbit, and guinea pig.
pubmed:affiliation
Burdon Sanderson Cardiac Science Centre, University Laboratory of Physiology, Parks Road, Oxford OX1 3PT, UK.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't