Interaction between thromboxane A2 and 5-hydroxytryptamine in the radial artery compared to the internal thoracic artery.
The aim of the present study was to investigate if the function of 5-hydroxytryptamine-1B/1D (5-HT1B/1D) receptors in human radial artery (RA) and internal thoracic artery (ITA) can be modified by thromboxane A2 (TXA2) released from the vessel wall in these two arteries that are commonly used in coronary artery bypass grafts. The 5-HT1B/1D agonist sumatriptan contracted the RA with a maximum response of 23.5+/-6.8 mN and a pD2 value of 6.6+/-0.1. The effect of sumatriptan was significantly reduced in the ITA with a maximum of 5.8+/-2.7 mN (P<.05) and a pD2 value of 6.4+/-0.2. The TXA2 receptor antagonist SQ30741 inhibited contractions to sumatriptan in the RA but not in the ITA. It is concluded that the effect mediated by 5-HT1B/1D is augmented by endogenous TXA2 in the RA.
Chester
A H
AH
Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College of Science Technology and Medicine, Heart Science Centre, Harefield Hospital, Middlesex UB9 6JH, Harefield, UK. adrian.chester@harefield.nthames.nhs.uk
Amrani
M
M
Sproson
C A
CA
Yacoub
M H
MH
D000368:Aged; D006801:Humans; D066298:In Vitro Techniques; D008323:Mammary Arteries / Q000187:drug effects* / Q000502:physiology; D008875:Middle Aged; D017534:Radial Artery / Q000187:drug effects* / Q000502:physiology; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; D011985:Receptors, Serotonin / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology*; D018170:Sumatriptan / Q000494:pharmacology; D013928:Thromboxane A2 / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects
C470302:HTR1B protein, human; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; D011985:Receptors, Serotonin; D012701:Serotonin; D013928:Thromboxane A2; D018170:Sumatriptan