Linked Life Data

8419544

Source:http://linkedlifedata.com/resource/pubmed/id/8419544

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-2-9
pubmed:abstractText
Chronic exposure of rats to nicotine increases the number of [3H]nicotine binding sites in the brain; however, it is not clear whether nicotinic cholinergic receptor function is altered as well. In this study, we have used [3H]tetraphenylphosphonium as a probe of synaptosomal membrane potential to investigate whether exposure to nicotine in vivo alters the ability of cerebral cortical synaptosomes to maintain a potential difference and to depolarize in response to in vitro nicotine. Treatment of rats for 14 days with 0.475 mg of nicotine base/day via subcutaneously implanted minipumps resulted in a decrease in the synaptosomal accumulation of [3H]tetraphenylphosphonium in physiological buffer, corresponding to a decrease in estimated membrane potential from -55 mV to -50 mV. The onset of the decrease in membrane potential occurred after 7 days of in vivo nicotine treatment and was significantly correlated with an increase in [3H]nicotine binding to cerebral cortical synaptosomal (P2) membranes. Nicotine, at in vitro concentrations of 3-1,000 microM, decreased [3H]tetraphenylphosphonium accumulation in cerebral cortical synaptosomes from control animals. When compared to accumulation in buffer alone, in vitro nicotine and other nicotinic agonists did not significantly decrease [3H]tetraphenylphosphonium accumulation in cerebral cortical synaptosomes prepared from rats treated with nicotine in vivo. These studies provide evidence that chronic treatment with nicotine results in an average lower membrane potential in cerebral cortical synaptosomes and in functional down-regulation of the depolarization response to nicotinic cholinergic receptor stimulation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0022-3042
pubmed:author
pubmed:issnType
Print
pubmed:volume
60
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
687-95
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Effects of chronic nicotine treatment on the accumulation of [3H]tetraphenylphosphonium by cerebral cortical synaptosomes.
pubmed:affiliation
Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee 53226.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't