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Figure 8 | Respiratory Research

Figure 8

From: The dopamine D1receptor is expressed and facilitates relaxation in airway smooth muscle

Figure 8

Dopamine D 1 receptor-mediated guinea pig airway relaxation is Epac independent. (A) Representative tension tracing in guinea pig tracheal ring after an acetylcholine contraction followed by increasing concentrations of the dopamine D1-like receptor agonist A68930 (1 - 100 μM) in the presence or absence of the Epac antagonist NSC45576 (250 μM). Top tracing is A68930 alone, and bottom tracing represent treatment with A68930 after 15 min pretreatment with NSC45576. (B) The effect of pretreatment with NSC45576 (250 μM) on A68930 (1 - 100 μM)-mediated tracheal ring relaxation. Open circles: A68930 alone. Filled circles: NSC45576 + A68930. Means ± SEM. N = 4. (C) Representative tension tracing in guinea pig tracheal ring after an acetylcholine contraction followed by increasing concentrations of β-adrenoceptor agonist isoproterenol in the presence or absence of NSC45576 (250 μM). Top tracing is isoproterenol alone, and bottom tracing represent treatment with isoproterenol after 15 min pretreatment with NSC45576. (D) Isoproterenol concentration-response curves comparing treatment with isoproterenol alone (open circles) to isoproterenol after pretreatment with NSC45576 (250 μM) (filled circles). *P < 0.05 compared with isoproterenol alone. N = 5.

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