Comparative distribution of cholinomimetic and parasympathetic contractile responses in the major diameter airways of dogs.

摘要: Summary The distribution of cholinomimetic and parasympathetic contractile responses in the major diameter airways simultaneous change lung resistance was examined 10 mongred dogs vivo. animals anesthetized with chloralose-urethane were insufflated tantalum, airway generations 0 (trachea) through 5 assessed as (dDaw) at functional residual capacity (FRC). All had β-adrenergic blockade propranolol to block reflex sympathetic effects resulting from hypotension. Sequential dose-response curves −10 −7 mol/kg iv methacholine (MCh; n=5) elicited; separate studies, stimulus-response generated (1–20 Hz; 7 min intervals. Tantalum bronchograms obtained each point on stimulus/dose-response curve for animal. Maximal stimulation caused a 28.8±4.35% dDaw trachea, 37.2±2.33% generation 1 42.4±3.63% airways. In contrast, substantially less narrowing trachea (dDaw=8.04±2.60%; P 95% maximum elecited Hz airways; increased progressively (from 2.38±0.62 38.9±4.12 cm H 2 O/L/s) over full range Hz). These data demonstrate substantial differences changes between elicited by vagus nerve comparable caliber Parasympathetic response characteristic also differs peripheral