Effect of Tramadol on Rabbit Uterine Contractile Activity Induced in Late Pregnancy.

Effect of Tramadol infusion (5 mg/ml) on oxytocin-induced uterine contractile activity was studied in chronic experiment on female rabbits with different degrees of biological readiness for parturition. In case of sufficient biological readiness for parturition, Tramadol did not change the number of uterine contractions, but increased the amplitude and duration of each contraction against the background of increased creatine phosphate consumption by the myometrium. At the same time, Tramadol infusion to females without biological readiness for partirition suppressed induced uterine contractile activity by reducing the amplitude of each uterine contraction.

[The influence of the bupivacaine epidural anesthesia on the rabbit myometrium contractile activity and the functional state of the fetuses in induced labor].

BACKGROUND: The influence of bupivacaine (0.5% - 1 ml) epidural anesthesia (EA) on 15 pregnant rabbit females induced in labor by oxytocin on the 30th day of pregnancy in chronic experiment was conducted. MATERIALS AND METHODS: 26 pregnant rabbit females took part in the investigation. 11 females were included in the control group and 15--to the main group. Both groups retrospectively were divided in two on the fact of the delivery during the experiment. For each 5-minute interval the contractile activity of the myometrium (number of uterine contractions, duration and amplitude of the one uterine contraction), functional state of fetuses and female (ECG) were evaluated. Registration of the parameters was carried out simultaneously with the help of electrodes which were administrated in the myometrium, to the fetuses and females on the 28th day of pregnancy. RESULTS: It was shown that EA influence on the myometrium contractile activity and functional state of fetuses and female depends on the female delivery readiness. CONCLUSION: In the case of the optimal one short-term increase of the contractile activity (on the 15th minute after EA) with no significant fetal heart rate changes were observed. In the case of its absence no significant influence was revealed. Moderate female tachycardia in both groups under EA was registered more pronounced in delivery one group.

[The influence of the bupivacaine regional anesthesia on the contractile activity of the uterus and the functional state of the fetus].

The study in chronic experiment on 26 pregnant rabbit females induced in labor by oxytocin on the 30th day ofpregnancy was conducted. The effects of bupivacaine (0,5% - I ml) epidural anesthesia (EA) on the contractile activity of the uterus, the functional state of the females and their fetuses were studied. On the 28th day of pregnancy under thiopental anesthesia electrodes were administered: to thefetus - ECG, in the female myometrium for recording electrical activity. In order to check the uterus mechanical activity the original sensor was used filled by graphite, which was placed around one horn of the uterus. The contractile activity of the myometrium was evaluatedfor each 5-minute interval by the number ofuterine contractions, duration and amplitude of one uterine contraction. The functional state offemale fetuses and rabbit female were evaluated by the frequency change of the heart rate. In 12 females occured to delivery. Registration of uterine contractions, heart rate of the female and fetuses were carried out simultaneously and continuously throughout the whole experiment. It was shown that under standard conditions EA didn't induce changes in uterine activity parameters of the female located in its natural position, and didn't affect on the fetal heart rate (3-factor analysis of variance - ANOVA). 10minutes after EA, the momentary acceleration of female heart rate (9%) was recorded in relation to the reference level, which may be associated with transient hypotension. Thus, in conditions of our experience the bupivacaine (0,5% - 1,0 ml) EA in induced labor of female rabbit has no significant effect on the uterus contractile activity and the functional state of the fetus. Short-term adaptive tachycardia is registered in females.

[The effect of experimental fever in female rabbits on the temperature homeostasis of their fetuses]. / Vliianie éksperimental'noi likhoradki u samok krolika na temperaturnyi gomeostaz ikh plodov.

I.v. administration of interleukin-1 induced an increment of body temperature in female rabbits. The temperature gradient between female rabbit and its underdeveloped foetus decreased more obviously than between normally developed foetus and female rabbit. This different reaction is associated with the hemodynamics specifics in placenta and foetuses. An increase of the gradient as compared with initial values during the restoration of normal body temperature suggests a more considerable disturbance of the uterus-placenta circulation and a worsening of the foetus state during this phase of the fever.

[Thermoregulatory parameters of normal and developmentally retarded newborn rat pups]. / Nekotorye parametry termoreguliatsii u normal'nykh i otstavshikh v razvitii novorozhdennykh krysiat.

The millicalorimetry with simultaneous recording of the motor activity, temperature of the brown adipose tissue and rectal temperature revealed a dysfunction of the brown adipose tissue and motor activity as the sources of additional heat production in the drop of ambient temperature in underdeveloped newborn rats.

[Isolation and partial characterization of poly-(a)+mRNA of soybean grown in the presence of gibberellic acid]. / Vydelenie i chastichnaia kharakteristika poli-(A)+mRNK soi, vyrashchennoi v prisutstvii gibberellovoi kisloty.

Poly(A)+mRNA was prepared by chromatography on the oligo (dT)-cellulose column from total RNA of epicotyls of soybean grown on the medium with gibberellic acid. Poly(A)+mRNA was prepared by the same method from control plants. Total RNA, poly-A and poly(A)+mRNAs were analyzed by electrophoresis on 1.5% agarose gel under denaturing conditions. The poly(A)+mRNA distribution was shown to be of polydispersional character, cDNA was synthesized by reverse transcription. Basing on cDNA-poly(A)+mRNA hybridization a conclusion is drawn that gibberellic acid may activate new types of mRNAs and, probably, increases the synthesis of some poly(A)+mRNA populations.

[The development of the activity-rest cycle in the rabbit fetus]. / Formirovanie tsikla aktivnost'-pokoi ploda krolika.

On 25-30-day rabbit foetuses, in chronic experiments using constant synchronous recording of the motor activity and heart rate, studies have been made of temporal organization of the activity-rest cycle. Already in 25-day foetus, three functional conditions may be distinguished: active, intermediate and resting ones, the duration of the latter increasing to the end of gestation up to 8-10 min, whereas the duration of the intermediate phase decreases, reaching its minimum to the 30th day if not being completely reduced. Cyclic pattern of active and resting phases is observed in 28-day foetuses; to the 29th-30th day, these phases from a unique activity-rest cycle, its duration reaching 20-30 min to the end of intrauterine period. It is suggested that the resting phase in foetal rabbits serves as a basis for the development of polyphasic sleep in adult animals.

Contractile activity of rabbit uterus at the end of pregnancy and a method for its registration.

We developed a method for synchronous registration of electrical activity of the myometrium in pregnant rabbit females and electrocardiograms of the female and fetus on a paper tape and on PC in the online mode using an original pickup for registration of intrauterine pressure in awaken animals in a natural (sitting) posture. The method causes no pregnancy complications and is adequate for evaluation of uterine contractility, female and fetal status in different variants of the experiment.

[Compensatory-adaptive responses of the rabbit fetuses developed under different intrauterine conditions, to noradrenaline administration].

In 9 experimental rabbit fetuses (with reduced uterine-placental blood frow), noradrenaline administration led to an obvious thermogenic response and heart rate increase, but not in intact rabbits. Obviously the noradrenaline dosage corresponds to the range of adaptive capacities of the functional systems in intact fetuses and so does not induce any shifts of the homeostasis parameters in them. The experimental fetuses prove to be more vulnerable to stresses, and homeostasis parameter shifts in them are statistically significant.

Fluorescent microscopic study of epithalon binding in maternal and fetal rabbit tissues in health and under conditions of placental insufficiency.

Epithalon (regulatory tetrapeptide) labeled with dansil (fluorescent stain) easily penetrates into all tissues and organs of pregnant rabbit females and through the placenta into fetal organs. Incorporation of labeled epithalon in placental tissues is more often observed in fetuses developing under conditions of placental insufficiency than in normal fetuses.

[The thermogenic characteristics in the early ontogeny of rats developing normally and under conditions of decreased uterine-placental blood circulation]. / Osobennosti termogeneza v rannem ontogeneze krys, razvivavshikhsia normal'no i v usloviiakh umen'shennogo matochno-platsentarnogo krovoobrashcheniia.

The brown adipose tissue was shown to be the main source of heat production in 1-day old rats, whereas by the 4th day their heat production becomes associated with non-contractile as well as contractile thermogenesis. Retarded rats revealed a disturbed adaptation to ambient conditions and they were unable to maintain their temperature homeostasis.

[Changes in hemodynamic parameters and temperature regimen in the system mother-placenta-fetus as affected by various drugs]. / Izmeneniia gemodinamicheskikh pokazatelei i temperaturnogo rezhima v sisteme mat'-platsenta-plod pod vliianiem nekotorykh lekarstvennykh preparatov.

In the chronic experiments at the end of pregnancy the effects of the infusion to mother of some drugs (trental, reopolyglucin and their combination) on the female of a rabbit and its fetuses normally developed and growth retarded were studied. It was found that changes in the intensity of maternal-placental blood flow, induced by the infusion of drugs to mother lead to the changes of gradient between temperature of fetus and mother, which reflect intensity of feto-placental blood flow and consequently the intensity of fetal heat loss. The possible unfavourable influence of these drugs on fetus temperature regimen and consequently on its metabolic processes under the treatment of placental insufficient and growth retardation have been taken into consideration.

[The development of interrelationships between the activity-rest cycle and thermoregulation in rabbit fetuses]. / Razvitie vzaimootnoshenii mezhdu tsiklom aktivnost'--pokoi i termoreguliatsiei plodov krolika.

The gradient of temperatures of the foetus and mother was found to increase along with an increase of the gestation age which coincides with an increase in the mass of grey fat tissue. In artificial placenta insufficiency, the activity-rest cycle of the foetuses is delayed by 1 or 2 days in their development. The mechanisms of thermoregulation were shown to start forming by 4 or 5 days earlier than the activity-rest cycle, the character of their functioning being comparable to that in poikilothermic animals.

[Thermoregulatory reaction in the rabbit fetuses developing under the reduced utero-placental blood flow]. / Osobennosti termoreguliatornykh reaktsii plodov krolika, razvivavshikhsia v usloviiakh umen'shennogo matochno-placentarnogo krovotoka.

Rectal temperature, temperature of the brown adipose tissue, and the heart rate were studied in the rabbit foetus under intact and reduced utero-placenta blood flow in the end of the intrauterine development. With the reduced utero-placenta blood flow, bradycardia and a drop in the brown fat metabolism due, probably, to an insufficient development and functional immaturity of this tissue, were revealed.

[Adaptive thermoregulatory reactions of the rabbit fetus at the end of the intrauterine development]. / K mekhanizmu adaptivnykh termoreguliatornykh reaktsii plodov krolika v kontse vnutriutrobnogo razvitiia.

The data of permanent simultaneous registration of electrocardiogram, rectal & brown adipose tissue temperatures of the rabbit foetus have been obtained in chronic experiments. The haemodynamic shift in intensity of maternal-placental and foeto-placental blood flow (by female trental injection) led to a decrease in the foetus rectal temperature (0.33 +/- 0.09 degree C in intact foetus and 0.58 +/- 0.27 degree C in retarded foetus, p < 0.05). Both foetuses reacted by rectal temperature decrease (0.65 +/- 0.28 & 0.68 +/- 0.31 degree C, respectively) during immobilisation (by foetus arduan injection). Thus in both series of experimental cooling of foetus, brown fat activation was similar in intact foetus (approximately 53%), but did not change in growth retardation foetus--as a result of its tissue functional immaturity, probably.

[Cold-induced paralysis and recovery of lung respiration and heart contractions in newborn rats (inversion of Arrhenius law for physiological functions)]. / Kholodovoi paralich i vosstanovlenie legochnogo dykhaniia i sokrashchenii serdtsa u novorozhdennykh krysiat (ob inversii zakona Arreniusa dlia fiziologicheskikh funktsii).

Arrest of respiration and heart activity in new-born rats aged 3-4 days and 10-11 days was shown to occur at a body temperature 6-7 degrees C and 2-3 degrees C lower than in adult rats, resp. At room temperature the body temperature of profoundly cooled rat's litter gradually increases and the functions are restored. In 3-4-day old rats, at the body temperature rising from profound cooling to 15-18 degrees C, the respiration and heart rates are 2-4-fold more than at the same temperature attained from the normal body temperature. These differences in the respiration and heart rates at the same body temperature suggest an inversion of the Arrhenius law (the Q10 coefficient) for physiological functions in early ontogenesis. This effect completely disappears in 10-11-day old rats.