ABSTRACT
We considered the influence of the neurons of intramural ganglia in the reaction of the smooth muscle trachea and bronchi caused by electric field stimulation, by the action of histamine. We studied the effect of neurons of intramural ganglia in the activity of the smooth muscle trachea and bronchi in the action of low doses of histamine (0,1 and 10 µg/ml), L-NAME and hexamethonium. It was shown the blockade of neuronal transmission decreased the contraction of the smooth muscles trachea and bronchi by stimulation of the afferent nerve structures. The smooth muscle relaxation under the influence of hexamethonium was also reduced. Histamine and hexamethonium increased contractile activity and increased the amplitude of the relaxation of the trachea and bronchi. The inhibition of NO- synthesis did not affect on the contraction, but reduced the relaxation of the trachea and bronchi. Histamine and L-NAME enhanced contractile activity, but not modified smooth muscle relaxation. Concluded that the neurons of intramural ganglia have an inhibitory effect on the smooth muscle of the trachea and bronchi and may have a modulating effect on contraction and dilatation of the smooth muscles of the airways.
Subject(s)
Bronchi/innervation , Histamine Agonists/pharmacology , Histamine/pharmacology , Neurons/drug effects , Trachea/innervation , Animals , Bronchi/physiology , Enzyme Inhibitors/pharmacology , Female , Ganglionic Blockers/pharmacology , Hexamethonium/pharmacology , Male , Muscle Contraction , Muscle Relaxation , Muscle, Smooth/innervation , Muscle, Smooth/physiology , NG-Nitroarginine Methyl Ester/pharmacology , Rats , Rats, Wistar , Trachea/physiologyABSTRACT
Influence of low concentration histamine on reactivity isolated trachea and bronchus preparations of rat induced field stimulation were studied. Application of 0.01-10 mkg histamine decreased responses preparation of trachea to 83% and bronchus to 79% at smooth muscle stimulation dose-depended manner. At postganglionic nerves stimulation histamine potentiated contraction of trachea without ganglions to 123%, trachea with ganglions to 110% and decreased contraction of bronchus to 87%. At stimulation ofpreganglionic nerves histamine evoked insignificant changes of contraction. With novocaine treatment of preparations histamine decreased responses of trachea by 19-30% at preganglionic stimulation, while responses of bronchus reduced by 8.2% only. Capsaicin treatment potentiated responses of trachea and bronchus on the effect of histamine induced preganglionic stimulation by 12-14%. We conclude that the action of histamine depends on the presence of ganglions and kind of stimulation. Different structures airways have various availability histamine-receptors and it determines the reaction of smooth muscle for histamine.
