β-Nicotinamide adenine dinucleotide: a novel bronchodilator inducing increase in intracellular cAMP

Introduction: β-Nicotinamide adenine dinucleotide (β-NAD) has been reported to relax vascular and intestinal smooth muscle via purinergic P2Y1 and P2Y11 receptors, and we recently demonstrated its relaxing activity on murine and human airway smooth muscle. This bronchodilator activity, however, was independent from purinergic receptors, and occurred concomitantly with increases in intracellular calcium concentration and cell depolarization. We here set out to further evaluate intracellular signaling pathways induced by β-NAD in airway smooth muscle. Methods: The relaxing effect of β-NAD was investigated by force…