Effect of prolonged exposure to brain-derived neurotrophic factor (BDNF) on intracellular Ca²⁺ ([Ca²⁺]_i) responses to agonist stimulation in human airway smooth muscle (ASM) cells.

<p>Figure shows representative tracings (A, C) and summaries of peak and plateau [Ca²⁺]_i responses (B, D) of ASM cells to 10 µM histamine (A, B) and 1 µM ACh (C, D) following 24 h exposure to vehicle (control), 1 nM BDNF, or 500 nM of the novel agonist 7,8-dihydroxyflavone which specifically activates the high-affinity BDNF receptor tropomyosin related kinase B (TrkB). The enhancing effects of BDNF and 7,8-dihydroxyflavone were comparable, suggesting that BDNF acts via TrkB in mediating effects on [Ca²⁺]_i. Values are means ± SE (n = 4 patients). *Significant difference from control (p<0.05).