Article date: May 1999
By: Peter De Vries, Edwin W Willems, Jan P C Heiligers, Carlos M Villalón, Pramod R Saxena, in Volume 127, Issue 2, pages 405-412
It has previously been shown that the antimigraine drug sumatriptan constricts porcine carotid arteriovenous anastomoses via 5‐HT1‐like receptors, identical to 5‐HT1B/1D receptors. The recent availability of silent antagonists selective for the 5‐HT1B (SB224289) and 5‐HT1D (BRL15572) receptor led us to further analyse the nature of receptors involved.
In pentobarbitone‐anaesthetized, bilaterally vagosympathectomized pigs, sumatriptan (30, 100 and 300 μg kg−1, i.v.) dose‐dependently decreased carotid arteriovenous anastomotic conductance by up to 70±5%.
The dose‐related decreases in carotid arteriovenous anastomotic conductance by sumatriptan (30, 100 and 300 μg kg−1, i.v.) remained unchanged in animals treated (i.v.) with 1 mg kg−1 of BRL15572 (maximum decrease: 72±3%), but were significantly attenuated by 1 mg kg−1 (maximum decrease: 30±11%) and abolished by 3 mg kg−1 (maximum decrease: 3±7%) of SB224289. The highest dose of SB224289 did not attenuate the hypertension, tachycardia or increases in carotid blood flow induced by bolus injections of noradrenaline (0.1–3 μg kg−1, i.v.).
The results indicate that sumatriptan constricts porcine carotid arteriovenous anastomoses primarily via 5‐HT1B, but not via 5‐HT1D receptors.
It has previously been shown that the antimigraine drug sumatriptan constricts porcine carotid arteriovenous anastomoses via 5‐HT1‐like receptors, identical to 5‐HT1B/1D receptors. The recent availability of silent antagonists selective for the 5‐HT1B (SB224289) and 5‐HT1D (BRL15572) receptor led us to further analyse the nature of receptors involved.
In pentobarbitone‐anaesthetized, bilaterally vagosympathectomized pigs, sumatriptan (30, 100 and 300 μg kg−1, i.v.) dose‐dependently decreased carotid arteriovenous anastomotic conductance by up to 70±5%.
The dose‐related decreases in carotid arteriovenous anastomotic conductance by sumatriptan (30, 100 and 300 μg kg−1, i.v.) remained unchanged in animals treated (i.v.) with 1 mg kg−1 of BRL15572 (maximum decrease: 72±3%), but were significantly attenuated by 1 mg kg−1 (maximum decrease: 30±11%) and abolished by 3 mg kg−1 (maximum decrease: 3±7%) of SB224289. The highest dose of SB224289 did not attenuate the hypertension, tachycardia or increases in carotid blood flow induced by bolus injections of noradrenaline (0.1–3 μg kg−1, i.v.).
The results indicate that sumatriptan constricts porcine carotid arteriovenous anastomoses primarily via 5‐HT1B, but not via 5‐HT1D receptors.
British Journal of Pharmacology (1999) 127, 405–412; doi:10.1038/sj.bjp.0702572
DOI: 10.1038/sj.bjp.0702572
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