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An endothelial 5‐HT receptor that mediates relaxation in guinea‐pig isolated jugular vein resembles the 5‐HT 1D subtype
Author(s) -
Gupta Paul
Publication year - 1992
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1992.tb14398.x
Subject(s) - rauwolscine , endocrinology , medicine , spiperone , ketanserin , 5 ht receptor , yohimbine , methysergide , receptor , chemistry , receptor antagonist , biology , pharmacology , serotonin , antagonist
1 Endothelium‐dependent and ‐independent, concentration‐related, relaxations to 5‐hydroxytryptamine (5‐HT) are described in a preparation of guinea‐pig isolated jugular vein. 2 An endothelial 5‐HT receptor was studied in the presence of mesulergine (at 10.0 μ m , a concentration sufficient to antagonize 5‐HT 2 receptor‐mediated contractions and endothelium‐independent relaxations to 5‐HT). Relaxations mediated by the endothelial 5‐HT receptor were resistant to antagonism by mesulergine. 3 Several 5‐HT receptor agonists activated the endothelial receptor with the following rank order of potency: 5‐carboxamidotryptamine (5‐CT) > 5‐HT > methysergide ≥ α‐methyl‐5‐HT > sumatriptan > 8‐hydroxy‐2‐(di‐n‐propylamino)tetralin (8‐OH‐DPAT) > 2‐methyl‐5‐HT. 4 Relaxations to 5‐HT were not blocked by (±)‐pindolol (1.0 μ m ), (−)‐propranolol (1.0 μ m ), spiperone (1.0 μ m ), ondansetron (1.0 μ m ) or ICS 205–930 (10.0 μ m ). 5 Both 5‐HT and sumatriptan evoked endothelium‐dependent relaxations which were sensitive to antagonism (pA 2 and apparent pA 2 values respectively) by methiothepin (8.1 and 8.6), metergoline (7.4 and 7.5), PAPP (8.2 and 8.2), yohimbine (7.1 and 6.8), rauwolscine (6.8 and 6.7), but not by corynanthine (10.0 μ m ). 6 These observations are consistent with a 5‐HT 1D receptor‐mediated effect, and provide further support for the concept that differences exist between endothelial 5‐HT receptors in different tissues and species.