The effect of dopamine receptor stimulation on the motor and stereotypic activities of mice with different genotypes]

On mice of 8 highly inbred strains--BALB/c, DBA/2, C57B1/6, CBA, DD, CC57Br, C3H/He, A/He--the role was studied of dopamine receptors of the first and second types (D1 and D2) in the regulation of the general motor activity and stereotypic climbing. Significant dependence was shown of these types of dopamine-dependent behaviour on the genotype. Agonist of D1/D2 receptors, apomorphine decreased the motor activity of animals of the all studied strains, and this effect significantly depended on the genotype. The inhibition of locomotion after selective stimulation of D2 receptors (by LY 171555) was significant. Distribution of mouse strains according to expressiveness of climbing after administration of apomorphine differed from their distribution by the level of motor activity. Selective stimulation of D1 receptors, on the whole, elicited climbing of lesser intensity than D1/D2 activation (excluding CBA strain), and administration of D2 agonist did not induce it at all. Probably, for full expression of behavioural reactions the interaction between D1 and D2 receptors is required.     

The effect of phencyclidine on dopamine metabolism in the mouse brain

The administration of phencyclidine (PCP) to mice resulted in no change in brain levels of tyrosine, dopamine (DA), norepinephrine (NE), or homovanillic acid (HVA). Although PCP reduced plasma tyrosine levels, no effect of PCP on the utilization of DA of NE after blockade of synthesis with α-methyl-p-tyrosine (AMPT) was observed. In addition, PCP did not affect the probenecid-induced accumulation of HVA. However, PCP was observed to potentiate the haloperidol-induced increase in HVA concentration, and the haloperidol-induced decline in DA levels after AMPT. The former effect was blocked by baclofen, suggesting that PCP mobilizes DA for impulse-dependent release. This effect could not be attributed to an antagonism of presynaptic DA receptors. These effects are similar to those of the “non-amphetamine” stimulant class of drugs.     

Eyeglass frame for detection of eye, head movements and pupillary diameter]

Up till now, the simultaneous recording of the movements of the eyes, the movements of the head and the diameter of the pupil required the combined use of several apparatus. In this paper we present a new apparatus developed for the simultaneous recording of the movements of the eyes and of the head, and the diameter of the pupil. The apparatus consists of a portable frame (weight 215 g) a 19" rack containing electronics, and a PC for storing and analyzing the recorded data. In comparison with other systems providing similar measuring possibilities the present apparatus has the advantage of smaller dimensions and lower weight.     

The effect of branch diameter on primate gait sequence pattern

Most mammals use lateral sequence gaits during quadrupedal locomotion, a pattern characterized by the touchdown of a forelimb directly following the ipsilateral hind limb in a given stride cycle. Primates, however, tend to use diagonal sequence (DS) gaits, whereby it is the touchdown of a contralateral forelimb that follows that of a given hind limb most closely in time. A number of scenarios have been offered to explain why primates favor DS gaits, most of them relating to the use of the arboreal habitat and, in particular, the exploitation of a narrow branch niche. This experimental study explores the potential explanation for the use of DS gaits by examining the relationship between branch diameter and gait patterns in 360 strides collected from six species of quadrupedal strepsirrhine primates on broad and narrow diameter supports. Gait sequence is quantified using limb phase, or the percentage of time during a stride cycle that a forelimb touchdown follows an ipsilateral hind limb touchdown. Although Loris, Nycticebus and Eulemur rubriventer individuals in this study did exhibit significantly lower locomotor velocities on narrower supports (P<0.01 in all three species), analyses of covariance showed no significant differences in limb phase values between broad and narrow diameter supports. Hence, results indicate surprisingly little evidence to suggest that alterations in gait sequence pattern provide a specific advantage for negotiating narrow supports.     

The effect of irradiation on dopamine level and metabolism in the rat brain

In experiments on rats it was shown that after 20 Gy irradiation dopamine and homovanilic acid content increases in the caudate nucleus and limbic structures of the forebrain: dopamine disappears more readily when its biosynthesis is blocked. The rate of the mediator degradation in the brain increases by 1.5-2 times, and the rate of the synthesis, by 3-5 times at early times after irradiation.     

The effect of the diameter of cyclic peptide nanotube on its chirality discrimination

In this work, the transport behaviors of the enantiomers of lactic acid (LA) in two cyclic peptide nanotubes (CPNTs) with different diameters were studied using steered molecular dynamic (SMD) simulation to investigate the effect of the diameter of CPNT on the discrimination of the enantiomers of LA. For this purpose, two cyclic peptides with two different sizes ([Ala-_D-Ala-_L]₅ and [Ala-_D-Ala-_L]₄) were used for constructing two CPNTs so that each CPNT was composed of eight cyclic peptide units. The docking calculations were performed to obtain the appropriate position of each enantiomer at the lumen of each CPNT. The variation of the pulling force versus time, exerted on the enantiomers moving in the CPNTs was calculated using the SMD simulations with two different strategies (positional and directional).The obtained results showed that the diameter of CPNT has considerable effect on the discrimination of the LA enantiomers so that the increase of the diameter of CPNT, increased the velocity difference between two enantiomers and improved the performance of CPNT for the chirality discrimination. The SMD simulations indicated that the velocity of S-enantiomer became more than R-enantiomer and its motion became more comfortable than R-enantiomer when the diameter of CNPT increased. The RDFs of the H and O atoms of the LA enantiomers relative to the O atoms of CPNT were calculated and it was found that the increase of the diameter of CPNT creates the significant changes in the RDFs of H1, H2 and H3 atoms of the enantiomers.     

The pupillary effects of oploids

Morphine's miotic action on the pupil is an easily recognizable and quantifiable effect in man. The neural pathways responsible for regulating pupil size are reasonably well defined. Yet, the mechanisms behind this and related effects of opioids on the eye in humans and laboratory animals have just begun to be explored. In this review, we have attempted to organize the available information on pupillary actions of opioids, emphasizing the dynamic nature of the responses, their species specificity, possible mechanisms of action, and the recently discovered development of tolerance to these actions. Our current knowledge regarding differences among the opioids, the effects of endogenous opioid peptides and the role of the various opiate receptor subtypes in pupillary effects is also summarized.     

The effect of hypergravity on carcinogenesis in mice

In recent years, investigators began studying the effect of hypergravity on pathological developments in the animal and human body. It was shown that a regular exposure of tail suspended rats to normal gravity diminished osteopenia and muscle atrophy. Moderate gravitational loading produced by a G-suit dramatically increased the therapeutic success rate in children with cerebral palsy. Rotation of patients with obliterating endarteritis and limb bone fractures in a short-radius centrifuge in hospitals of the city of Samara (Russia) yielded promising results. The purpose of our investigations was to investigate the effects of hypergravity on chemically induced carcinogenesis in mice. We hypothesized that gravitational loading may produce a generalized effect on the animal body and thus to enhance its nonspecific anti-tumor resistance.     

Effect of dopamine on immune cell proliferation in mice

Dopamine is known as a precursor of catecholamine and one of the neurotransmitters in brain and peripheral tissues. Recent studies suggest an important role of dopamine in immune responses. In the present study, intraperitoneal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) which lowered endogenous dopamine suppressed splenocyte proliferation in response to mitogens such as lipopolysaccharide (LPS) and concanavalin A (Con A). Moreover, intravenous injection of the specific agonists of dopamine DA-1 receptor (SKF38393) or DA-2 receptor (LY171555) into mice enhanced the splenocyte proliferation stimulated by LPS or Con A. In the in vitro cultures, dopamine, SKF38393 and LY171555 directly promoted cell proliferation to LPS or Con A. These results indicate that dopamine has an ability to regulate B- and T-cell proliferation both in vivo and in vitro.     

The effect of theophylline on the diameter of the afferent glomerular arteriole of the rat]

Agar-agar and indian ink mixture intrarenal injections enable the precise glomerular afferent arteriole diameter and the evaluation of its variations after theophyllin perfusion. The increased diameter (+ 35, 78 %) confirms the peripheral vasodilating theophyllin effect, never to our knowledge proven in situ in the kidney.     

The position effect in mice on day 14

Previous publications have produced conflicting results concerning the effect and nature of uterine horn position on embryonic weight and development in the uterus bicornis. For this investigation we used 503 embryos from 41 litters of NMRI - mice on gestational day 14. The relative position of each embryo was determined by measuring the distance from the center of each placenta to the cervix in relation to the total length of the uterine horn. After cessation of shrinkage due to fixation the umbilical cord and remaining membranes were removed under the dissecting microscope and the embryos were weighed to the nearest 0.1 mg. Analysis of potential embryonic positions along the uterine horns indicated that 10% at the extreme ovarian and cervical ends were almost devoid of implantations. A mixed nested analysis of variance was used as the appropriate model to test a position on weight effect. Not only was a position effect found but, in contrast to other studies, it is also quantitatively represented. Embryos were lighter both at the ovarian and cervical ends, the mean weight difference being in the range of less than 10% of the average embryo weight.     

大黄酸对糖尿病小鼠肠道菌群影响的初步研究

目的研究大黄酸对2型糖尿病模型(db/db小鼠)和正常对照模型(db/m小鼠)肠道菌群丰度、种类的影响。方法将db/db小鼠和db/m小鼠分为随机分为实验组、对照组,在标准饮食的基础上分别给予大黄酸溶液(120mg/kg)和纤维素钠溶液(1%)灌胃,分别于实验0、2、3周无菌收集小鼠粪便,进行V3-V5、V5-V6高可变区16SrDNA基因组测序,分析四组小鼠肠道菌群组成结构和菌落多样性的变化,并比较各组间差异。结果大黄酸治疗后两组小鼠拟杆菌明显增多,硬壁菌明显减少,两组小鼠肠道菌群多样性指数(Shannon-Wiener指数)治疗后均降低。db/db组小鼠血糖较对照组降低(t=3.499,P=0.013)。结论大黄酸可以增加db/db小鼠和db/m小鼠肠道中拟杆菌数量,减少硬壁菌数量,同时db/db小鼠和db/m小鼠肠道菌群多样性在大黄酸治疗后都降低。     

The effect of thymectomy on lupus-prone mice

The effect of neonatal thymectomy on the induction and/or modification of murine SLE disease was examined in several representative groups of mice with early-life SLE (MRL/Mp-lpr/lpr females, BXSB males, (NZB X W)F1 females, (NZW X BXSB)F1 males and females), late-life SLE (MRL/Mp-+/+ and BXSB females), and normal strains (BALB/c and C57BL/6 females). Our results indicated that thymectomy prevented disease only in the MRL/Mp-lpr/lpr SLE mice, and that this effect diminished as thymectomy was delayed beyond 3 wk post-natally. In the other SLE mice studied, neonatal thymectomy did not modify disease symptoms to any significant degree. Moreover, depletion of mature T cells from donor BXSB male bone marrow did not affect the expression of early-life SLE in thymectomized BXSB female recipients. Neonatal thymectomy did not induce SLE in normal mice. Of note, neonatal thymectomy did not completely deplete the Thy-1.2+ cell population, i.e., 10 to 15% remained in the spleens of the thymectomized mice. This incomplete T cell depletion, together with the previously demonstrated dependence on and hyperresponsiveness of BXSB and (NZB X W)F1 B cells to T helper cell-derived accessory signals, cast doubts on earlier conclusions that B cells from some SLE mice can autonomously proliferate and differentiate to autoantibody-secreting cells. It seems more appropriate to conclude that B cells from the various SLE mice vary in their degree of response to, and production of, T cell-derived helper signals, and thus in their expression of B cell hyperactivity and disease.