Prostanoid receptors involved in the relaxation of human bronchial preparations

Abstract

1 Iloprost and cicaprost (IP-receptor agonists) induced relaxations in the histamine-(50 mM) contracted human bronchial preparations (pD 2 values, 6.63+0.12 and 6.86+0.08; E max values, 90+04 and 65+08% of the papaverine response for iloprost (n=6) and cicaprost (n=3), respectively).2 Prostaglandin E 2 (PGE 2 ) and misoprostol (EP-receptor agonist) relaxed the histamine-contracted human bronchial preparations (pD 2 values, 7.13+0.07 and 6.33+0.28; E max values, 67+04 and 57+08% of the papaverine response for PGE 2 (n=14) and misoprostol (n=4), respectively). In addition, both relaxations were inhibited by AH6809 (DP/EP 1 /EP 2 -receptor antagonist; 3 mM; n=5 ± 6). 3 The PGE 2 -induced relaxations of human bronchial preparations were not modi®ed by treatment with AH23848B (TP/EP 4 -receptor antagonist; 30 mM; n=4). 4 The contracted human bronchial preparations were signi®cantly relaxed by prostaglandin D 2 (PGD 2 ) or by BW245C a DP-receptor agonist. However, these responses did not exceed 40% of the relaxation induced by papaverine. In addition, the relaxations induced by PGD 2 were signi®cantly inhibited by treatment with a DP-receptor antagonist BWA868C (0.1 mM; n=3). 5 These data suggest that the relaxation of human isolated bronchial preparations induced by prostanoids involved IP-, EP 2 -and to a lesser extent DP-receptors but not EP 4 -receptor.

Selective Prostacyclin Receptor Agonism Augments Glucocorticoid-Induced Gene Expression in Human Bronchial Epithelial Cells

“…Thus, there appears to be a PGI 2 deficiency in emphysematous COPD and a reciprocal increase in TXA 2 generation with predicted undesirable effects on platelet reactivity and pulmonary vascular smooth muscle function. Clearly, a selective IP-receptor agonist could restore this PGI 2 /TXA 2 imbalance and, thereby, reduce the threshold for platelet aggregation (71), lower pulmonary vascular resistance (72) (through smooth muscle relaxation and, long term, by inhibiting mitogenesis), and even promote bronchodilatation (73). The results of this study indicate that an IP-receptor agonist could also suppress airway and pulmonary vascular inflammation by enhancing the clinical efficacy of an ICS.…”

Effects of Plastoquinones from the Brown Alga Sargassum micracanthum and a New Chromene Derivative Converted from the Plastoquinones on Acute Gastric Lesions in Rats

“…Inhibitory Effects of AH6809 on Contraction in Isolated Gastric Fundus of Rats 12,13) The experiment was carried out using Magnus method. 14) Male Sprague-Dawley rats were fasted for about 16 h and killed by exsanguination.…”

Prostaglandin D2 is a potent chemoattractant for human eosinophils that acts via a novel DP receptor

“…PGE 2 has 4 receptor subtypes (EP 1-4 receptors), whereas PGs D 2 , F 2␣ , I 2 , and thromboxane (TX) A 2 each have a single receptor (DP, FP, IP, and TP receptors, respectively). 1 The DP receptor is coupled positively to adenylyl cyclase through G s , 1 and this results in a strong inhibitory effect on platelet aggregation 2 as well as bronchodilator 3 and vasodilator 4 effects in humans. The DP receptor and lipocalin-type PGD synthase are both abundant in the central nervous system, where PGD 2 plays a role in regulating sleep 5 and pain perception.…”