[Mechanism of action of naphthoquinones and hydroxycoumarins on the mechano-active properties of isolated coronary arteries]. / K mekhanizmu deistviia naftokhinonov i oksikumarinov na mekhanoaktivnye svoistva izolirovannykh koronarnykh arterii.

The action of natural naphthoquinones and their antagonists oxicoumarins on mechanoactive properties of isolated coronary arteries was studied in experiments on male albino rats. Vitamin K deficiency (primary, secondary) was found to be accompanied with disturbances of mechanoactive properties of the heart vessels Naphthoquinones (vitamins K1 and K3) exerted a spasmolytic action on coronary vessels of intact animals and animals with vitamin K deficiency as well. These effects are supposed to be probably related to the redistribution of cations Ca2+ and K+ in membranes.

[Effect of nitroglycerin on the calcium mechanism regulating the tonus of large and small coronary arteries]. / Deistvie nitroglitserina na kal'tsievyi mekhanizm reguliatsii tonusa krupnykh i melkikh koronarnykh arterii.

It has been established in experiments on isolated ring-shaped strips of large and small coronary artery of the dog that nitroglycerin produces a more pronounced and prolonged relaxation of the myocytes of large coronary arteries at the expense of the inhibition of transmembranous transport and intracellular exchange of calcium ions. In small coronary arteries, nitroglycerin inhibits transmembranous transport of calcium ions, exerting no antagonistic effect on the exchange of intracellular calcium ions. Thus, the different effect of nitroglycerin on the tone of large and small coronary arteries is accounted for by different sensitivity to the drug action of the depot of intracellular calcium ions in the myocytes of these objects.

[Effect of static loads on the contractile activity of myocytes of the small coronary arteries]. / Vliianie staticheskoi nagruzki na sokratitel'nuiu aktivnost' miotsitov melkikh koronarnykh arterii.

The effect of initial stationary exertion on the mechanical activity of vessels' smooth muscles was studied under the potassium activation of the electromechanical coupling in the myocytes in the dog small coronary arteries of 400-500 mu in diameter. Increase of the load from 120 to 240 mg potentiated the contractile responses to administration of potassium ions into the vascular chamber and led to electromechanical type of coupling activation in the smooth muscles due to increased inflow of the calcium ions into the myocytes. Intracellular fractions of calcium ions seem not to participate in this process.

[Effect of nitroglycerin on the tonus of isolated coronary arteries]. / Vliianie nitroglitserina na tonus izlirovannykh koronarnykh arterii.

It has established on isolated ring-like strips of large coronary arteries of the dog that spasmolytic effects of nitroglycerin are related to its antagonistic action on Ca2+ and are not completely pharmacomechanic. The action of nitroglycerin is not related to beta-adrenoreceptors of the coronary arteries and apparently is not mediated through an increase in the intracellular pool of cyclic AMP.