5-hydroxytryptamine is a mediator of 4-aminopyridine induced contractions in porcine and human isolated coronary arteries

Attila Kun, J. Pataricza, Irén Krassói, Miklós Opincariu, János Szécsi, J. Papp

Research output: Contribution to journalArticle

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Abstract

The effect of 4-aminopyridine (4-AP), a known inhibitor of voltage-dependent K+ channels (Kv), was studied on the resting vasomotor tone in porcine and human coronary arteries. Isolated coronary artery preparations were suspended in organ bath for isometric tension recordings. 4-AP (1.25×10-8 5.8×10-4 M) caused concentration-dependent contractions both in porcine and human coronary arteries. The EC50 values obtained with 4-AP did not differ significantly in porcine and human coronary preparations (-4.54 logM and -4.37 logM, respectively). Loading the amine stores of the coronary tissues with 1 mM noradrenalin or blocking the beta-receptors with 2 μM propranolol did not change the contractile effects of 4-AP. In contrast, loading the isolated blood vessels with 1 mM 5-hydroxytryptamine (5-HT) resulted in significantly higher contractions, when induced by micromolar concentrations of 4-AP. The 5-HT receptor blocker, methysergide, almost completely inhibited these contractions. Our present observation provides evidence for the functional role of Kv in setting the vasomotor tone of coronary arteries through the release of 5-HT. In the light of these findings we suggest that the porcine coronary artery preparation can serve as a model for studying the functional effect of drugs on KV-type potassium channels.

Original languageEnglish
Pages (from-to)39-44
Number of pages6
JournalActa Biologica Szegediensis
Volume44
Issue number1-4
Publication statusPublished - 2000

Fingerprint

4-aminopyridine
4-Aminopyridine
coronary vessels
serotonin
Serotonin
Coronary Vessels
Swine
swine
potassium channels
Methysergide
propranolol
Serotonin Receptors
Potassium Channels
Blood vessels
norepinephrine
amines
Baths
blood vessels
Propranolol
Amines

Keywords

  • 4-aminopyridine
  • Human coronary artery
  • Porcine coronary artery
  • Voltage-dependent potassium channel

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Cell Biology
  • Applied Microbiology and Biotechnology
  • Neuroscience(all)

Cite this

5-hydroxytryptamine is a mediator of 4-aminopyridine induced contractions in porcine and human isolated coronary arteries. / Kun, Attila; Pataricza, J.; Krassói, Irén; Opincariu, Miklós; Szécsi, János; Papp, J.

In: Acta Biologica Szegediensis, Vol. 44, No. 1-4, 2000, p. 39-44.

Research output: Contribution to journalArticle

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AU - Opincariu, Miklós

AU - Szécsi, János

AU - Papp, J.

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AB - The effect of 4-aminopyridine (4-AP), a known inhibitor of voltage-dependent K+ channels (Kv), was studied on the resting vasomotor tone in porcine and human coronary arteries. Isolated coronary artery preparations were suspended in organ bath for isometric tension recordings. 4-AP (1.25×10-8 5.8×10-4 M) caused concentration-dependent contractions both in porcine and human coronary arteries. The EC50 values obtained with 4-AP did not differ significantly in porcine and human coronary preparations (-4.54 logM and -4.37 logM, respectively). Loading the amine stores of the coronary tissues with 1 mM noradrenalin or blocking the beta-receptors with 2 μM propranolol did not change the contractile effects of 4-AP. In contrast, loading the isolated blood vessels with 1 mM 5-hydroxytryptamine (5-HT) resulted in significantly higher contractions, when induced by micromolar concentrations of 4-AP. The 5-HT receptor blocker, methysergide, almost completely inhibited these contractions. Our present observation provides evidence for the functional role of Kv in setting the vasomotor tone of coronary arteries through the release of 5-HT. In the light of these findings we suggest that the porcine coronary artery preparation can serve as a model for studying the functional effect of drugs on KV-type potassium channels.

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