Effect of pyrrolidone-pyroglutamic acid composition on blood flow in rat middle cerebral artery.

We compared the effects of a pyrrolidone-pyroglutamic acid composition and nimodipine on blood circulation in the middle cerebral artery in rats. The composition produced a strong effect on blood supply to the brain, stimulated blood flow in the middle cerebral artery (by 60 +/- 9%) and decreased blood pressure (by 25.0 +/- 2.7%). The cerebrovascular effects of this composition differed from those of nimodipine. Nimodipine not only increased middle cerebral artery blood flow, but also decreased cerebral blood flow in the early period after treatment.

[Changes in the blood circulation in the middle cerebral and common carotid arteries of rats under the influence of flunarizine]. / Izmeneniia krovoobrashcheniia v srednei mozgovoi i obshchei sonnoi arteriiakh krys pod vliianiem flunarizina.

Experiments conducted on Wistar rats under general anesthesia using the Doppler ultrasonic method showed that flunarizine caused a slowly developing (for 20 min), moderate (25%), and prolonged (90 min) increase of the blood flow in the middle cerebral artery. In the common carotid artery the drug induced two-phase changes in blood circulation. The initial increase in the blood flow was replaced by its reduction below the basic level.

[Nimodipine, nifedipine and the cerebrovascular effects of serotonin]. / Nimodipin, nifedipin i tserebrovaskuliarnye éffekty serotonina.

Experiments on rats with the use of ultrasonic techniques demonstrated that serotonin causes an initial significant decrease in the blood flow in the channel of the middle cerebral artery followed by a mild increase in the blood supply to the brain. It was shown in in vivo experiments that nimodipine and nifedipine do not prevent the development of serotonin-induced constriction of the vessels of the middle cerebral artery channel. At the same time, the cerebrovascular effects of nimodipine and nifedipine are significantly weakened under the action of serotonin.

[Circulatory changes in the middle cerebral artery and the carotid arteries of rats under the influence of nifedipine]. / Izmeneniia krovoobrashcheniia v srednei mozgovoi i sonnykh arteriiakh krys pod vliianiem nifedipina.

The experiments on Wistar rats with Doppler ultrasonography [correction of echocardiography] have shown that nifedipine causes a substantial and longterm circulatory increase in the middle cerebral artery. With nifedipine, blood flow increases in the common and internal carotids to a lesser extent, the changes being less long, and outstrip the responses of cerebral vessels in time.

[Effectiveness of artificial ventilation in oil microembolism followed by pulmonary edema]. / Effektivnost' iskusstvennoi ventiliatsii pri maslianoi mikroémbolii i posleduiushchem oteke legkikh.

In experiments on sodium pentobarbital (40 mg/kg, i.p.) anesthetized mongrel cats of either sex weighting from 2.0 to 4.0 kg, it was found, that in conditions of oil pulmonary microembolization, followed by pulmonary edema, the most suitable is rapid and shallow pattern of ventilation, ensuring optimal ventilation/perfusion interrelation. The oil microembolization was introduced with intravenous administration (1 mg per kg of body weight during 2 min) of olive oil. It is necessary to provide flexible regimens of artificial ventilation and conformity of respiratory pattern and body's demands can be controlled according to pHa and PaO2. It is desirable that pH and pO2 can be evaluated continuously.

[An experimental model of apneusis and periodic respiration]. / Eksperimental'naia model' apneizisa i periodicheskogo dykhaniia.

In experiments on sodium pentobarbital (40 mg/kg, i. p.) anesthetized mongrel cats of either sex weighting from 2.0 to 4.0 kg, it was stated, that sodium or lithium hydroxybutyrate (HOB) (200 mg/kg, i. v.) effectively slowed down breathing with inspiratory holdings. Thus 3-5 minutes after HOB administration, eupneic pattern of respiration was changed firstly to inspiratory apneustic one (100% of cats), and then to periodic one (80% of cats). This pattern persisted for 60-90 minutes, and after that the respiratory pattern usually changed its direction to the opposite one. In these conditions alterations of arterial blood composition (pH, pO2, pCO2, SO2) and hemodynamic variables (heart rate, arterial pressure) can not be considered as the cause of apneustic pattern of respiration. It is suggested, that HOB can be used for simulating such terminal respiratory patterns as apneustic and periodic ones.

[Extracellular pH, [K+] and synaptic transmission in the dorsal horn of spinal cord of rats in hypercapnia]. / Vnekletochnyi pH, [K+] i sinapticheskaia peredacha v dorsal'nom roge spinnogo mozga krys pri giperkapnii.

In rats anaesthetized with +-chloralose the changes in extracellular pH and K+ in spinal cord dorsal horn were studied using pH and K+ ion-selective electrodes. The addition of 20% CO2 into inhaled air decreased the basal level of [pH]0 from 7.35 +/- 0.01 to 6.78 +/- 0.09 pH units and increased the basal level of [K+]0 from 3.1 +/- 0.1 to 5.14 +/- 0.8 mM. Electrocutaneous supramaximal (10 mA) simulation of both hind paws with the frequency 30 and 100 Hz induced the shift in the concentration of H+ and K+ by 0.15-0.2 unit and 2-2.5 mM, respectively. Under hypercapnia this shift of pH decreased by 36.9 +/- 8.5% at 30 Hz frequency of electrocutaneous stimulation and by 41.9 +/- 6.1% at 100 Hz frequency. The K+ shift decreased by 11.5 +/- 1.3% and by 17.3 +/- 1.5% under similar conditions. Hypercapnia induced by addition of 20% CO2 into inhaled air decreased also the focal potential amplitude by 16.8 +/- 4%. Thus, hypercapnia induces the increase of [K+]0 and [pH]0 and the decrease of recorded indicators in response to electrocutaneous stimulation. Total depression of synaptic transmission and analgetic effect occur due to these changes of ions distribution.