[Action of noradrenaline and acetylcholine on the contractile activity of the gastric arteries]. / Deistvie noradrenalina i atsetilkholina na sokratitel'nuiu deiatel'nost' arterii zheludka.

The effects of norepinephrine and acetylcholine on smooth muscle cells of isolated strips of gastric arteries were studied. The gastric arteries revealed small sensitivity to acetylcholine. The norepinephrine effects on smooth muscle cells can be realized through electrogenic and pharmacomechanical activation. The adrenergic control of gastric arteries is fulfilled mainly with alpha-adrenoreceptors participation.

[Activation mechanisms of the contractile cells of cerebral arteries and veins]. / Issledovanie mekhanizmov aktivatsii sokratitel'nykh kletok mozgovykh arterii i ven.

In isolated strips of internal carotid artery and middle cerebral artery in humans, spontaneous electric and contractile activities were revealed. Low (35 degrees C) and high (40--41 degrees C) temperatures inhibited the development of spontaneous contractions. Under depolarization of the cells' membranes by potassium ions, no development of spontaneous electric or contractile waves occurred, while contractions of the tonic type were observed in arterial preparations. No spontaneous contractions were found in the cerebral veins.

[Effect of depolarizing factors on the contractile activity of the smooth muscle of stomach vessels]. / Deistvie depoliarizuiushchikh faktorov na sokratitel'nuiu aktivnost' gladkoi muskulatury sosudov zheludka

In isolated strips of the pig left gastral artery, potassium and electrical stimulation were shown to elicit gradual contractile responses of the contracture type. This effect was abolished by the blockage of calcium permeability of the membranes with manganese ions. Fast stretching evoked no contractile response, while the slow one potentiated the contraction. Activation of the smooth muscle contractile apparatus seems to be due to calcium extracellular ions coming into the cell during depolarization of membrane. Further functioning of the contractile mechanism and the final physiological effect depend on interaction of the membraneous and intracellular links of electromechanical conjugation controlling the intracellular concentration of the calcium ions.

[Activation mechanisms for contractions of the smooth musculature of the cerebral vessels]. / Mekhanizmy aktivatsii sokrashenii gladkoi muskulatury mozgovykh sosudov

Pial arteries and veins were found to differ by their contractile features. Pial arteries are highly sensitive to noradrenaline, adrenaline, histamine, serotonin, rapid stretching, and potassium ions. The effects of the mediators, potassium ions, and rapid stretching could be blocked by manganese ions. Pial veins are insensitive to the mediators effects, potassium ions, or rapid stretching, although they are highly sensitive to transmural electric stimulation. Manganese ions have no effect on the veins' responses to electric stimulation. A spontaneous activity of the smooth muscle cells of the a. carotis' intracranial portion was revealed in man. The activation mechanisms for the cerebral arteries smooth muscle contractions are suggested to depend on the calcium extracellular ions. The activation mechanism for the veins' smooth muscle contractions depends on the intracellular store of calcium ions.