Effects of a cotton bract extract on guinea pig isolated airway smooth muscle.
Fedan-JS; Franczak-MS; Cahill-JF; Kosten-CJ; Morey-PR; Weber-KC
J Toxicol Environ Health 1986 Jan; 18(2):189-204
Isolated guinea pig trachealis smooth muscle preparations were exposed to cotton bract water extract (CBE) to investigate the ability of the extract to evoke tension responses, to modify tissue reactivity to excitatory and inhibitory agents and to modify electric field stimulation induced neurogenic responses. Addition of up to 3 milligrams per liter (mg/l) CBE caused contraction; tension declined in response to higher concentrations. Contractions were not mediated by histamine-H1 receptors, muscarinic receptors, or 5-hydroxytryptamine receptors. Maximum contractile response to 5- hydroxytryptamine and sensitivity to postassium-chloride were reduced in the presence of CBE. Maximum relaxatory responses and sensitivities to adenosine and adenosine-triphosphate were increased by CBE. Contractile responses to histamine and methacholine and relaxation responses to isoproterenol were unaffected. CBE did not appear to affect neurogenic cholinergic excitatory responses or neurogenic adrenergic responses. The relaxant effect of nonadrenergic inhibitory nerve stimulation was increased in the presence of CBE. Most contractile activity remained in the CBE after dialysis or ashing. Based on comparison with previous studies in the dog, the authors conclude that the effects of CBE in isolated airways may be species dependent. CBE does not appear to influence cholinergic excitatory neurotransmission. Inorganic components of the CBE may contribute to its contractile action.
NIOSH-Author; Pulmonary-system-disorders; Laboratory-animals; Muscle-contraction; Electrical-stimulation; Nervous-system; Muscle-function
Journal of Toxicology and Environmental Health