Regulation of smooth muscles of the vascular wall in the rabbit pulmonary artery

The cholinergic, histaminergic and adrenergic features of regulation of the small muscles contractile activity in a vascular wall of a pulmonary artery in rabbits and involvement of an endothelium in these processes, were investigated. The cholinergic release phenomenon of small muscles of the rabbit pulmonary artery has a two-component character of dose dependence. The low-threshold components of Pilocarpinum relaxing effect has an endothelium-dependent nature. The important feature of histaminergic regulation of contractile activity of segments involves a direct contractile effect of histamine that is not inherent. The endothelium renders a suppressing effect on histaminergic contraction of small muscles of the rabbit pulmonary artery. A basic feature of adrenergic regulation of the pulmonary artery involves registered-beta-adrenergic contractile effects in small muscles of a vascular wall. The activation of the cAMP-dependent signal system in small muscles of a pulmonary artery is capable of rendering a contractile effect. The detected features of a regulation in the small circle can have an essential clinical-physiological value.