Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Editor

Personal info

View

About

Terms

Javascript disabled

Please enable Javascript support in your browser to use this application.

Instructions on how to enable JavaScript on different browsers can be found here: http://www.google.com/support/bin/answer.py?answer=23852.

[edit this page]

Frenken, M. et al.

Effects of tryptamine mediated through 2 states of the 5-HT2 receptor in calf coronary artery.

The mode of action of tryptamine was investigated on strips of left circumflex coronary artery of calf. 1) Exposure to (-)-deprenyl, an irreversible inhibitor of monoamine oxidase B, markedly potentiated the contractions caused by tryptamine but not those by 5-hydroxy-tryptamine (5-HT). Experiments were therefore carried out on arteries treated with (-)-deprenyl. 2) Tryptamine, administered non-cumulatively, elicited fast developing contractions, which partially faded. The intrinsic activity for the peak response to tryptamine was 0.8 compared to 5-HT. Ketanserin competitively antagonized the tryptamine-induced contractions with a KB of (-log mol/l) 9. 9. Methysergide antagonized the effects of tryptamine in a noncompetitive manner by depressing the maximum response with an IC50 (-log mol/l) greater than 9. 0. 3) Tryptamine caused unsurmountable depression of 5-HT-induced contractions with an IC50 (-log mol/l) of 6. 4. Ketanserin also competitively antagonized the depressant effects of tryptamine on 5-HT-induced contractions with a KB of (-log mol/l) 9. 9. 4) At high concentrations of tryptamine (0.2-1 mmol/l), the fast developing contractions were followed by slowly developing contractions. Methysergide 1 nmol/l enhanced maximally the slow developing contractions. 5) These findings are consistent with an interaction of tryptamine at different sites of the allosteric 5-HT2-receptor system: (I) Tryptamine competes with ketanserin for the 5-HT2-receptor in the highly active R state. Binding of tryptamine to the R state would cause the fast contraction. (II) Tryptamine competes with ketanserin for the allosteric sites.(ABSTRACT TRUNCATED AT 250 WORDS)[1]

References

Effects of tryptamine mediated through 2 states of the 5-HT2 receptor in calf coronary artery. Frenken, M., Kaumann, A.J. Naunyn Schmiedebergs Arch. Pharmacol. (1988) [Pubmed]

Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenes Open Access Licence Privacy Policy Terms of Use apsburg

The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.