Linked Life Data

9716515

Source:http://linkedlifedata.com/resource/pubmed/id/9716515

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 18
pubmed:dateCreated
1998-11-20
pubmed:abstractText
We have examined the accumulative transport properties of the Malpighian (excretory) tubules of the tobacco hornworm Manduca sexta to test the hypothesis that a P-glycoprotein-like multidrug transporter is active and is responsible for the excretion of dietary nicotine in this tissue. Isolated tubules were cannulated and exposed to radiolabelled forms of either nicotine (5 min exposure) or the P-glycoprotein substrate vinblastine (60 min exposure) in the bathing (basal surface) fluid. The luminal (apical) contents were then flushed, and lumen-to-bath ratios were measured. Although these ratios provide conservative estimates of the physiological ability of Malpighian tubules to move compounds from blood to lumen, tubules concentrated nicotine 10-fold from an initial bath concentration of 0.5 mmol l-1 and vinblastine threefold (from an initial concentration of 1 micromol l-1). Vectorial transport of vinblastine and nicotine was eliminated by 25 micromol l-1 verapamil (a P-glycoprotein inhibitor) and was not dependent on the presence of a transepithelial electrical potential. Nicotine transport was inhibited by atropine (3 mmol l-1), while nicotine (> or = 50 micromol l-1) significantly reduced vinblastine transport. Verapamil was effective at reducing vinblastine transport when applied to the basal side alone, but not when applied to the apical side alone. Taken together, these results are consistent with the idea that the active excretion of nicotine and other alkaloids by the tobacco hornworm is mediated by a P-glycoprotein-like mechanism.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0022-0949
pubmed:author
pubmed:issnType
Print
pubmed:volume
201
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2637-45
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Transepithelial transport of nicotine and vinblastine in isolated malpighian tubules of the tobacco hornworm (Manduca sexta) suggests a P-glycoprotein-like mechanism.
pubmed:affiliation
University of Ottawa, Department of Biology and Neurosciences, Loeb Research Institute, Ottawa Hospital, Ottawa, Ontario, Canada K1Y 4E9.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't