[Effect of noradrenaline on the electrical and contractile properties of smooth muscle cells in the pulmonary artery].
Experiments were performed on the smooth muscle cells of rabbit a. pulmonalis using the microelectrode technique. No spontaneous electrical or mechanical activity was recorded in normal Krebs solution. The current-voltage relation in these smooth muscle cells showed marked rectification. No changes in the isometric tension were observed due to the anodal or cathodal stimulating currents. Strong depolarization of the muscle cells produced only local potentials on the cathelectrotone which never developed into a spike. Noradrenaline (10(-8) g/ml) caused depolarization of the 5-7 mV in the muscle cell membrane and a considerable contraction of the muscle strip as well. Under such conditions the contractile apparatus of the muscle cells became sensible to the resting potential level. Anodal stimulation was accompanied by relaxation of the muscle strip, whereas cathodal stimulation--by its contraction. The alpha-adrenoblocking agent (phentolamine) blocked the effect of noradrenaline evidencing the fact that noradrenaline exerted its excitatory action on the smooth muscle cells of the a. pulmonalis through the alpha-adrenoreceptors.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects; D004558:Electric Stimulation; D004594:Electrophysiology; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000166:cytology; D011817:Rabbits
D000317:Adrenergic alpha-Antagonists; D009638:Norepinephrine
Vliianie noradrenalina na élektricheskie i sokratitel'nye svoĭstva gladkomyshechnykh kletok legochnoĭ arterii