[Pharmacokinetics of hopantenic acid upon peroral administration].

A simple, specific and sensitive RP-HPLC method with UV detection for the determination of hopantenic acid in human blood plasma has been developed. The pharmacokinetics of drug pantocalcin upon single peroral administration was investigated on 18 healthy volunteers. The peak of hopantenic acid in blood plasma was achieved at 1.56 h and the elimination half life was 6.68 h. No hopantenic acid in blood plasma is found in 48 h.

[Effect of calcium antagonists on ureteral contractile activity in experiment].

Dihydropiridine (nifedipine), phenilalkilamine (isoptin) and a novel domestic calcium channel blocker A-29 were studied for effects on motor activity of an isolated segment of a rabbit ureteral upper-third. Strength of muscular contractions (134 measurements) was evaluated in per cents to the baseline level. Tonic reaction and its duration were measured. Calcium antagonist action on ureteral contractile activity was studied by changes in contractile power in concentration rage from 10(-9) to 10(-5) M/l. Beginning from 10(-9) M/l concentration of all the drugs studied there was a gradual decline of the initial contractile activity of the ureter. The following concentrations of calcium antagonists significantly reduced the amplitude of phasic contraction, whereas therapeutic concentrations--by more than 40%. In elevation of the concentration in some cases washing of the isolated ureteral segment with Krebs' solution failed to reestablish tonic reaction. Only A-29 spontaneous contractile activity recovered after washing. The maximal effect was achieved with nifedipin and A-29 in concentrations 10(-5) M/l. Thus, calcium antagonists change contractile activity of smooth muscle cells of the ureter with a dose-dependent effect making it possible to use calcium antagonists for inhibition of contractile ureteral activity in clinical practice.

[Effect of ryodipine, fenigidin, verapamil, and manganese ions on the contractile strength and the myometrium potential duration during rhythmic stimulation and at rest]. / Vliianie riodipina, fenigidina, verapamila i ionov margantsa na silu sokrashcheniia i dlitel'nost' potentsialov miometriia pri ritmicheskoi stimuliatsii i v pokoe.

Action of the calcium channels blocking agents was studied using their strong but reversible concentrations, in different regimens. Riodypine and phenihydine suppressed the contraction strength and shortened the AP duration in the myometrium muscle stripes equally effectively both in resting and under stimulation (0.3 Hz). Verapamyl and manganese ions suppressed the contraction strength and shortened the AP duration more effectively under rhythmic stimulation than in resting.

[Effect of diumancal, foridon, nifedipine, and verapamil on the myometrium potentials in pregnant rats]. / Vliianie diumankala, foridona, nifedipina i verapamila na biopotentsialy miometriia beremennykh krys.

All the preparations under study were i.v. administered to pregnant Wistar rats in the doses adequate to therapeutic those on pregnant woman basis. Within 10 minutes, a drop both in the amplitude and in the rate of the myometrium potentials were found.

[Biological effect of laser radiation on the functional state of cardiomyocytes]. / Biologicheskoe deistvie lazernogo izlucheniia na funktsional'noe sostoianie kardiomiotsitov.

Experiments were conducted on Wistar rats to study the effect of laser radiation (LR) with a wavelength of 632.8 and 890.0 nm and power of 0.0005-0.005 and 0.003-0.003 W/cm2, respectively, on the action potential (AP) and mechanical contraction of smooth muscle cells, as well as myocardial ATPase activity. LR with a wavelength of 632.8 and 890.0 nm in a dose of 3.0 J/cm2 activates Ca-ATP-ase activity, increases the activity of the myocardial antioxidant system, reduces the Na-Ca current through the membrane, and accelerates the return of Ca2+ into the sarcoplasmic reticulum. LR with a wavelength of 632.8 nm reduces mainly the Ca flow, while LR with a wavelength of 890.0 nm reduces the Na current In a dose of more than 3.0 J/cm2 LR causes a damaging effect manifested by increased Ca2+ current in the slow channels, increase of amplitude, duration of AP and repolarization phase. Synergism of the action of LR with a wavelength of 632.8 and 890.0 nm and that of some antiarrhythmic agents (procainamide, lidocaine, ethmosin, ethacisin, verapamil) was encountered.

[The role of calcium permeability in shaping the level of the local blood supply to the cerebral cortex]. / O roli kal'tsievoi pronitsaemosti v formirovanii urovnia lokal'nogo krovoobrashcheniia kory golovnogo mozga.

Cerebral blood flow and the water content in the brain cortex were measured in rabbits with indwelling electrodes. Calcium antagonists increased the CBF in the motor area and decreased it in other regions of the brain.