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An amplifying effect of exogenous and neurally stored 5-hydroxytryptamine on the neurogenic contraction in rat tail artery

Szabo, Csaba; Hardebo, Jan Erik LU and Owman, Christer LU (1991) In British Journal of Pharmacology 102(2). p.401-407
Abstract
1. The interactions between sympathetic neuroeffector transmission and 5-hydroxytryptamine (5-HT) were investigated in segments of rat isolated tail artery. 2. Contractile responses to field stimulation of the artery segments were abolished by tetrodotoxin (3 x 10(-7) M). A subthreshold concentration of acutely applied exogenous 5-HT (10(-8) M) markedly enhanced the contractions induced by sympathetic nerve stimulation, through an action on postjunctional 5-HT2-receptors. 3. The amplifying effect of 5-HT involved an enhanced influx of extracellular calcium into the smooth muscle cells. In contrast, the neurogenic contractions in vessels not exposed to 5-HT were not dependent on extracellular calcium. 4. The adrenergic component of the... (More)
1. The interactions between sympathetic neuroeffector transmission and 5-hydroxytryptamine (5-HT) were investigated in segments of rat isolated tail artery. 2. Contractile responses to field stimulation of the artery segments were abolished by tetrodotoxin (3 x 10(-7) M). A subthreshold concentration of acutely applied exogenous 5-HT (10(-8) M) markedly enhanced the contractions induced by sympathetic nerve stimulation, through an action on postjunctional 5-HT2-receptors. 3. The amplifying effect of 5-HT involved an enhanced influx of extracellular calcium into the smooth muscle cells. In contrast, the neurogenic contractions in vessels not exposed to 5-HT were not dependent on extracellular calcium. 4. The adrenergic component of the amplified response involved postjunctional alpha 1- but not alpha 2- adrenoceptor activation. 5. Exposure of the vessels to 5-HT (5 x 10(-7) M) for 30 min resulted in uptake of the amine into the perivascular sympathetic nerves, as demonstrated by immunohistochemistry. After chemical sympathectomy with 6-hydroxydopamine in vitro or in vivo, or surgical sympathectomy, there was little or no uptake. 6. Exposure to 5-HT followed by repeated washing resulted in an enhancement of the neurogenic contraction, which was still fully tetrodotoxin-sensitive. The enhanced response was blocked by ketanserin (10(-8) M) and prevented by the presence of the 5-HT uptake blocker, paroxetine (3 x 10(-8) M), during the period of exposure to 5-HT. (Less)
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type
Contribution to journal
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published
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in
British Journal of Pharmacology
volume
102
issue
2
pages
401 - 407
publisher
The British Pharmacological Society
external identifiers
  • pmid:1849769
  • scopus:0026082880
ISSN
1476-5381
language
English
LU publication?
yes
id
f2e72828-5ff6-43e0-b858-069b28f78ff1 (old id 1105965)
alternative location
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1918028
date added to LUP
2008-08-01 12:02:03
date last changed
2017-01-01 07:14:14
@article{f2e72828-5ff6-43e0-b858-069b28f78ff1,
  abstract     = {1. The interactions between sympathetic neuroeffector transmission and 5-hydroxytryptamine (5-HT) were investigated in segments of rat isolated tail artery. 2. Contractile responses to field stimulation of the artery segments were abolished by tetrodotoxin (3 x 10(-7) M). A subthreshold concentration of acutely applied exogenous 5-HT (10(-8) M) markedly enhanced the contractions induced by sympathetic nerve stimulation, through an action on postjunctional 5-HT2-receptors. 3. The amplifying effect of 5-HT involved an enhanced influx of extracellular calcium into the smooth muscle cells. In contrast, the neurogenic contractions in vessels not exposed to 5-HT were not dependent on extracellular calcium. 4. The adrenergic component of the amplified response involved postjunctional alpha 1- but not alpha 2- adrenoceptor activation. 5. Exposure of the vessels to 5-HT (5 x 10(-7) M) for 30 min resulted in uptake of the amine into the perivascular sympathetic nerves, as demonstrated by immunohistochemistry. After chemical sympathectomy with 6-hydroxydopamine in vitro or in vivo, or surgical sympathectomy, there was little or no uptake. 6. Exposure to 5-HT followed by repeated washing resulted in an enhancement of the neurogenic contraction, which was still fully tetrodotoxin-sensitive. The enhanced response was blocked by ketanserin (10(-8) M) and prevented by the presence of the 5-HT uptake blocker, paroxetine (3 x 10(-8) M), during the period of exposure to 5-HT.},
  author       = {Szabo, Csaba and Hardebo, Jan Erik and Owman, Christer},
  issn         = {1476-5381},
  language     = {eng},
  number       = {2},
  pages        = {401--407},
  publisher    = {The British Pharmacological Society},
  series       = {British Journal of Pharmacology},
  title        = {An amplifying effect of exogenous and neurally stored 5-hydroxytryptamine on the neurogenic contraction in rat tail artery},
  volume       = {102},
  year         = {1991},
}