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Kinetic studies on uptake of serotonin and noradrenaline into pial arteries of rats

Chang, J Y; Hardebo, Jan Erik LU and Owman, Christer LU (1990) In Journal of Cerebral Blood Flow and Metabolism 10(1). p.22-31
Abstract
A population of cerebrovascular nerve fibers have recently been found to store serotonin (5-hydroxytryptamine; 5-HT). There is reason to assume that these 5-HT-containing fibers have a sympathetic rather than an intracerebral origin. This was further elucidated in the present study in which the uptake mechanisms of 5-HT and noradrenaline (NA) were characterized and compared in rat pial arteries by measuring the accumulation of [3H]5-HT and [14C]NA under various experimental conditions in vitro. Sympathectomized vessels served as blanks. The uptake into the perivascular sympathetic nerves was dependent on time as well as concentration and was saturable. The Km values were similar, 0.17 microM for 5-HT and 0.15 microM for NA, but the Vmax... (More)
A population of cerebrovascular nerve fibers have recently been found to store serotonin (5-hydroxytryptamine; 5-HT). There is reason to assume that these 5-HT-containing fibers have a sympathetic rather than an intracerebral origin. This was further elucidated in the present study in which the uptake mechanisms of 5-HT and noradrenaline (NA) were characterized and compared in rat pial arteries by measuring the accumulation of [3H]5-HT and [14C]NA under various experimental conditions in vitro. Sympathectomized vessels served as blanks. The uptake into the perivascular sympathetic nerves was dependent on time as well as concentration and was saturable. The Km values were similar, 0.17 microM for 5-HT and 0.15 microM for NA, but the Vmax value was 10 times higher for NA (2.38 and 25 pmol/mg/15 min, respectively). The two amines competed with each other in the sympathetic uptake, as studied by inhibition of the accumulation of one labeled amine by the other nonlabeled amine. Corticosterone, acting on the extraneuronal process, significantly inhibited the 5-HT uptake but had no substantial effect on NA. Reserpine, blocking the intraaxonal vesicular stores, markedly attenuated the accumulation of NA, but not of 5-HT. The selective uptake blocker paroxetine reduced the 5-HT uptake with much higher potency than the NA uptake, whereas desipramine predominantly inhibited NA uptake. The pial 5-HT uptake was not significantly affected by lesion of the raphe complex, whereas it was reduced to half following superior cervical ganglionectomy. The results suggest that the 5-HT present in nerves associated with pial vessels at the base of the brain is taken up through an efficient axonal mechanism, functionally related but not identical to the uptake process for NA. (Less)
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published
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in
Journal of Cerebral Blood Flow and Metabolism
volume
10
issue
1
pages
22 - 31
publisher
Nature Publishing Group
external identifiers
  • pmid:2298833
  • scopus:0025057682
ISSN
1559-7016
language
English
LU publication?
yes
id
e2fbb226-38a1-45b5-9929-b0650c85a5b6 (old id 1105374)
date added to LUP
2008-08-05 12:49:55
date last changed
2017-01-01 06:55:59
@article{e2fbb226-38a1-45b5-9929-b0650c85a5b6,
  abstract     = {A population of cerebrovascular nerve fibers have recently been found to store serotonin (5-hydroxytryptamine; 5-HT). There is reason to assume that these 5-HT-containing fibers have a sympathetic rather than an intracerebral origin. This was further elucidated in the present study in which the uptake mechanisms of 5-HT and noradrenaline (NA) were characterized and compared in rat pial arteries by measuring the accumulation of [3H]5-HT and [14C]NA under various experimental conditions in vitro. Sympathectomized vessels served as blanks. The uptake into the perivascular sympathetic nerves was dependent on time as well as concentration and was saturable. The Km values were similar, 0.17 microM for 5-HT and 0.15 microM for NA, but the Vmax value was 10 times higher for NA (2.38 and 25 pmol/mg/15 min, respectively). The two amines competed with each other in the sympathetic uptake, as studied by inhibition of the accumulation of one labeled amine by the other nonlabeled amine. Corticosterone, acting on the extraneuronal process, significantly inhibited the 5-HT uptake but had no substantial effect on NA. Reserpine, blocking the intraaxonal vesicular stores, markedly attenuated the accumulation of NA, but not of 5-HT. The selective uptake blocker paroxetine reduced the 5-HT uptake with much higher potency than the NA uptake, whereas desipramine predominantly inhibited NA uptake. The pial 5-HT uptake was not significantly affected by lesion of the raphe complex, whereas it was reduced to half following superior cervical ganglionectomy. The results suggest that the 5-HT present in nerves associated with pial vessels at the base of the brain is taken up through an efficient axonal mechanism, functionally related but not identical to the uptake process for NA.},
  author       = {Chang, J Y and Hardebo, Jan Erik and Owman, Christer},
  issn         = {1559-7016},
  language     = {eng},
  number       = {1},
  pages        = {22--31},
  publisher    = {Nature Publishing Group},
  series       = {Journal of Cerebral Blood Flow and Metabolism},
  title        = {Kinetic studies on uptake of serotonin and noradrenaline into pial arteries of rats},
  volume       = {10},
  year         = {1990},
}