The effects of (-)-cromakalim and glibenclamide on uptake2 in guinea-pig trachealis muscle

Bryan-Lluka L.J. and Vuocolo H.E. (1993) The effects of (-)-cromakalim and glibenclamide on uptake2 in guinea-pig trachealis muscle. Naunyn-Schmiedeberg's Archives of Pharmacology, 348 1: 65-69. doi:10.1007/BF00168538


Author Bryan-Lluka L.J.
Vuocolo H.E.
Title The effects of (-)-cromakalim and glibenclamide on uptake2 in guinea-pig trachealis muscle
Journal name Naunyn-Schmiedeberg's Archives of Pharmacology   Check publisher's open access policy
ISSN 0028-1298
Publication date 1993-01-01
Sub-type Article (original research)
DOI 10.1007/BF00168538
Open Access Status
Volume 348
Issue 1
Start page 65
End page 69
Total pages 5
Publisher Springer-Verlag
Subject 3004 Pharmacology
Abstract In a recent study, we have shown that hyperpolarization of cells by β-adrenoceptor agonists results in stimulation of the uptake2 process for catecholamines. The aim of the present study was to further explore the hypothesis that uptake2 is dependent on membrane potential by examining the effects of the K+-channel opening drug, (-)-cromakalim, and the K+-channel blocking drug, glibenclamide, on uptake2 of isoprenaline. The effects of these drugs were examined in guinea-pig trachealis muscle, in which isoprenaline and cromakalim cause hyperpolarization, and in rat heart, in which isoprenaline and cromakalim have little effect on membrane potential. In guinea-pig trachealis muscle segments, 1 μmol/l glibenclamide reduced uptake2 (as measured by the steady-state rate of corticosterone-sensitive formation of 3H-3-O-methylisoprenaline normalized for the isoprenaline concentration) in tissues incubated in concentrations of 3H-(±)-isoprenaline that hyperpolarize the muscle (25 and 250 nmol/l) but not at an isoprenaline concentration that did not hyperpolarize the muscle (1 nmol/l). (-)-Cromakalim (10 μmol/l), which hyperpolarizes the trachealis muscle, increased uptake2 of isoprenaline (1 or 25 nmol/l) and this effect of (-)-cromakalim was inhibited by glibenclamide. In rat hearts perfused with 1 or 25 nmol/l 3H-(±)-isoprenaline and 10 μmol/l U-0521 to inhibit catechol-O-methyltransferase, the rate of uptake2 of isoprenaline was unaffected by cromakalim or glibenclamide. The results show that hyperpolarization of cells by various mechanisms can result in stimulation of uptake2 of catecholamines and provide further evidence to support the hypothesis that the uptake2 transport process is driven by the membrane potential of cells.
Keyword Cromakalim
Glibenclamide
Guinea-pig trachealis
Isoprenaline
Membrane potential
Uptake2
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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