Transmural stimulation
Transmural stimulation, also called electrical field stimulation (EFS),
was performed by placing tissues between two wire platinum electrodes
(20 mm apart, Panlab Harvard Apparatus, Spain), connected to a 3165
multiplexing pulse booster stimulator (Ugo Basile, VA - Italy).
Bronchial rings were contracted by EFS at increasing frequencies
(EFS1-50Hz, 10V, 10s, 0.5ms, biphasic pulse) in order to
simulate the vagus nerve firing (parasympathetic pathway) observed in
human in vivo and thus producing frequency-response curves (FRCs) via
endogenous cholinergic contractile response (Cazzola et al., 2011).