title: Influence of bethanechol on retained particles deposited on the first bifurcation of rabbits.
abstract: Retention of 4 micron 51Cr labelled Teflon particles administered to nine male rabbits via trachea was measured externally. About 5 microliter of a suspension with a particle concentration of 40 mg X ml-1 was deposited on the first bifurcation through a fiberoptic bronchoscope under urethane anesthesia. Over a period of two weeks, the rabbits were exposed twice, under the influence of the cholinergic drug bethanechol chloride and in a control examination. The time period during which 90% of deposited particles had cleared was significantly shorter in the presence of bethanechol (16 h) than in the control experiment (70 h). The magnitude of the fraction which cleared within the first hour did not differ significantly for drug administration and control, being 39.0% and 36.8%, respectively. The fraction which did not clear within the first hour tended (p = 0.1) to clear faster, half-time 10.4 h, when bethanechol chloride was given than it did in the controls, half-time 31.3 h. A reasonable interpretation of the results is that the cholinergic compound, bethanechol, increases bronchial secretion, which results in a reversed movement of the particles that previously penetrated the mucous layer, back to the mucous layer.
mesh_terms: D000818:Animals; D018723:Bethanechol; D001626:Bethanechol Compounds / Q000494:pharmacology*; D001980:Bronchi / Q000502:physiology; D008168:Lung / Q000502:physiology*; D011138:Polytetrafluoroethylene; D011817:Rabbits; D013997:Time Factors; D014132:Trachea / Q000502:physiology
chemical_list: D001626:Bethanechol Compounds; D018723:Bethanechol; D011138:Polytetrafluoroethylene