Cannabinoid-serotonin interactions in alcohol-preferring vs. alcohol-avoiding mice

Because cannabinoid and serotonin (5-HT) systems have been proposed to play an important role in drug craving, we investigated whether cannabinoid 1 (CB1) and 5-HT(1A) receptor ligands could affect voluntary alcohol intake in two mouse strains, C57BL/6 J and DBA/2 J, with marked differences in native alcohol preference. When offered progressively (3-10% ethanol) in drinking water, in a free-choice procedure, alcohol intake was markedly lower (approximately 70%) in DBA/2 J than in C57BL/6 J mice. In DBA/2 J mice, chronic treatment with the cannabinoid receptor agonist WIN 55,212-2 increased alcohol intake. WIN 55,212-2 effect was prevented by concomitant, chronic CB1 receptor blockade by rimonabant or chronic 5-HT(1A) receptor stimulation by 8-hydroxy-2-(di-n-propylamino)-tetralin, which, on their own, did not affect alcohol intake. In C57BL/6 J mice, chronic treatment with WIN 55,212-2 had no effect but chronic CB1 receptor blockade or chronic 5-HT(1A) receptor stimulation significantly decreased alcohol intake. Parallel autoradiographic investigations showed that chronic treatment with WIN 55,212-2 significantly decreased 5-HT(1A)-mediated [35S]guanosine triphosphate-gamma-S binding in the hippocampus of both mouse strains. Conversely, chronic rimonabant increased this binding in C57BL/6 J mice. These results show that cannabinoid neurotransmission can exert a permissive control on alcohol intake, possibly through CB1-5-HT(1A) interactions. However, the differences between C57BL/6 J and DBA/2 J mice indicate that such modulations of alcohol intake are under genetic control.     

Effects of passive administration of serotonin and catecholamine antibodies on alcohol consumption of C57Bl/6 mice in experimental alcoholism]

The experiments on C57Bl/6 mice with natural ethanol motivation have shown that passive injection of anti-noradrenaline and particularly antiserotonin antibodies reduces several times alcohol consumption by animals. On the contrary the injection of anti-dopamine antibodies to affect voluntary alcohol consumption by mice have been found.     

Experimental diabetes in mice infected with Coxsackie viruses

The influence of Coxsackie B4 and AI3 viruses on the pancreas of mice (resistant and susceptible to diabetes) was studied. Glucose intolerance and changes in the synthesis of immunoreactive insulin were detected in all the treated groups of animals. Biochemical changes were more prominent in male DBA/2 mice, infected with Coxsackie B4 virus, in FI (CBA X C57Bl/6) hybrids and in female DBA/2 mice infected with Coxsackie AI3 virus and alloxan.     

Constitutive activation of the mTOR signaling pathway within the normal glomerulus

Fructose induces several kinds of human metabolic disorders; however, information regarding fructose-induced kidney injury is still limited. This study examined fructose-induced kidney injury in mice and clarified the differential susceptibility of three mouse strains: C57Bl/6J, CBA/JN and DBA/2N. In this study all mice were fed with an equal calorie count for sixteen weeks to remove the influence of total energy intake from metabolic effects by fructose-feeding. Only DBA/2N mice, but not C57Bl/6J and CBA/JN mice, fed with fructose displayed tubulointerstitial fibrosis localized on the outer cortex of the kidney together with the increase of mRNA expression of Kim1 and Ngal in the absence of distinct glomerular lesions and albuminuria - decidedly different from diabetic nephropathy. In time-course study of DBA/2N mice fed with fructose diet, the inflammation and fibrosis in the outer cortex of the kidney were enhancing after eight weeks, in parallel with the accumulation of oxidative stress. This progression of renal damage in DBA/2N mice was accompanied with increasing mRNA expression of GLUT5. These results suggest that the responsiveness of GLUT5 expression to fructose at the kidney is one of pivotal roles for the progression of fructose-induced kidney injury.     

Study of immunoregulating properties of an interferon inducer in animals with various reactions to the antigen

Influence of dsRNA isolated from killer yeast of S. cerevisiae on humoral and cellular immune responses in mice CBA/CaY and C57Bl/6Y with opposing reaction to the antigen was studied. It was shown that after administration of the yeast dsRNA preparation to the animals simultaneously with the antigen there was an increase in the number of the antibody forming cells in the spleen and the titer of hemolytic antibodies in blood serum of the animals with high and low reactions to the antigen. After sensitization with different doses of sheep red blood cells (10(7) and 10(8)) the preparation had immunomodulating action on development of DTH in mice CBA/CaY. The effect of the dsRNA preparation on the immunity system depended on the preparation dose, antigen loading and animal genotype and was the most marked in mice CBA/CaY with interferon levels in blood serum 2-3 times higher than those in mice C57Bl/6Y.     

Mechanism of the intensification of the immune response to Staphylococcus in mice after the transplantation of primed donor splenocytes

Experiments on CBA, C57Bl/6 mice and (CBA X X C57Bl/6)F1 hybrids were made to study the mechanism of stimulation of the immune response to staphylococci after injection of primed splenocytes. The stimulating action of immune splenocytes was reversed after their in-vitro treatment with anti-immunoglobulin serum and complement. The stimulant effect was also seen in a semi-allogeneic system (adoptive transfer of CBA mice immune cells to (CBA X C57Bl/6)F1 recipients). Preincubation of splenocytes with CBA-anti-C57Bl/6-serum and complement prior to demonstration of antibody-forming cells did not influence their number in the spleen of hybrid recipients injected with immune cells carrying parent genotype but decreased this indicator of the immune response in control mice. It is concluded that stimulation of the immune response to staphylococci after transplantation of primed splenocytes is due to the anamnestic response of donor's cells repeatedly stimulated by antigen in the recipient's host.     

Identification of two forms of an endogenous murine retroviral env gene linked to the Rmcf locus.

The Rmcf gene restricts the replication of recombinant murine mink cell focus-inducing (MCF) viruses in cell cultures derived from mice carrying the resistance allele (Rmcfr) and may play a role in resistance to retrovirus-induced leukemias in vivo. We have characterized the endogenous gp70 expressed by Rmcfr and Rmcfs mice with a panel of type-specific monoclonal antibodies which discriminate xenotropic and MCF gp70. Embryo and tail skin cultures derived from Rmcfr mice (DBA/2 and CBA/N) expressed gp70 bearing a determinant unique to MCF viruses, whereas cultures from Rmcfs mice expressed either no detectable gp70 (NFS/N and IRW) or a gp70 serologically related to a subgroup of xenotropic viruses (C57BL/6, CBA/J, and A/WySn). Studies of progeny embryos derived from a (C57BL/6 X DBA/2) X C57BL/6 backcross established that the Rmcf resistance allele was linked to the expression of the MCF gp70 and that the gene encoding the xenotropic gp70 expressed by C57BL/6 Rmcfs mice was allelic with the MCF gp70 from Rmcfr mice. These data indicate that the Rmcf locus contains an endogenous gp70 gene having two allelic forms, one of which inhibits exogenous MCF infection in vitro by a mechanism of viral interference.     

Postradiation volatile secretion and development of immunosupression effectes by laboratory mice with various genotype

The appearance of lines CBA and C57Bl/6 in the urine of mice irradiation volatile excretions with immunosupression property was associated with the violation at mice of ability to immunogenesis. It was established, that immunosupression activity of excretions irradiated mice CBA and C57Bl/6 did not depend on genotip of mice. However, by irradiated mice C57Bl/6 immunosupression components, depressing antibody formation at intact mice, appeared earlier, than at CBA. Immunosypression, limited postradiation volatile secretion in view of depression humoral immune response at intact mice kept for not a long time and mostly expressed on the course 2-3 days after exposition with postradiation secretion.     

Effect of retinoic acid on indices of humoral immunity

The influence of all-trans- and 13-cys-methylretinoate on antibacterial and antiviral immunity was studied in experiments on noninbred C57Bl/6 and (CBA X C57Bl/6) F1 mice. All-trans-methylretinoate was shown to stimulate the production of antibodies to E. coli antigens, with the effect being dose-dependent. At the same time both compounds inhibited the production of inhibitors, interferon and antibodies to influenza virus.     

Mouse serum inhibition of cytotoxicity of goat antibodies against mouse thymocytes]

It is shown that the serum of Balb/c, C57Bl/6 and F1(C57Bl/6 x CBA) mice inhibits cytotoxicity of goat antithymocyte antibodies. The addition of the serum into the incubation medium increases the proportion of alive cells from -5% up to 95%. Cytotoxicity was also inhibited by the globulin fraction of the mice serum. It is suggested that normal mice serum contains factors which block cytotoxicity of antibodies against antigen host determinants.     

A major influence of sex-specific loci on alcohol preference in C57Bl/6 and DBA/2 inbred mice

C57Bl/6 mice reproducibly prefer to ingest more 10% ethanol in a two-bottle choice paradigm than do DBA/2J mice. In this paper we report the identification of two new sex-specific alcohol preference (Alcp) loci. Melo and associates (1996) identified two loci: Alcp1, a male-specific locus on Chromosome (Chr) 2, and Alcp2, a female- and cross-specific locus on Chr 11. We have additionally identified Alcp3, a male-specific locus on Chr 3, and Alcp4, a female-specific locus on Chr 1. We have also performed a statistical analysis to exclude the possibility of undiscovered major alcohol preference loci that are not sex-specific in our backcross paradigm. Our results indicate that alcohol preference in C57BL/6 mice, as measured in our backcross, is largely controlled in a sex-specific manner. Received: 15 September 1998 / Accepted: 8 October 1998     

Influence of ionizing radiation on the attractiveness of male mice to chemosignals of intact individuals

Within short-terms after exposure to ionizing radiation, CBA and C57Bl/6 male mice were found not only to retain but also to enhance their attractiveness to chemosignals of intact males of the same genotype (syngenic). It was shown that the time period of higher attractiveness increased with the absorbed dose (from 1 to 6 Gy). Within several days after exposure to 6-Gy irradiation, male mice were temporarily unable to discriminate between chemosignals of syngenic and allogenic (alien genotype) individuals. Unlike male mice of the CBA strain, male mice of the C57Bl/6 strain displayed no changes after exposure to 1-Gy irradiation, but the effect of 2-6 Gy was more persistent. These phenomena can be explained by the lower olfactory reactivity combined with higher radiosensitivity of C57Bl/6 mice. Irradiated male mice temporarily lost their olfactory ability to discriminate the genotype of females' volatile secretions and to distinguish between females' and males' volatile secretions.     

Comparative evaluation of the biogenic amine level of the brain and the ethanol kinetics in the blood of inbred C57B1/6 and CBA mice

The kinetics of ethanol in blood and the levels of serotonin, noradrenaline, and dopamine in the cortex of cerebral hemispheres, hypothalamus, thalamus, and brain stem were studied in male C57C1/6 and CBA mice characterized by predisposition and non-predisposition to the development of experimental alcoholism. C57B1/6 mice characterized by predisposition to the development of experimental alcoholism demonstrated a high level of serotonin and noradrenaline in the hypothalamus and brain stem and high rate of ethanol elimination from the blood. CBA mice non-predisposed to the development of experimental alcoholism were characterized by a low level of serotonin and noradrenaline in the hypothalamus and brain stem and by low rate of ethanol elimination from blood.     

Enzyme activities and ethanol preference in mice

Alcohol dehydrogenase and aldehyde dehydrogenase, the two principal enzymes of alcohol metabolism, were assayed in the livers of the inbred mouse strains C57BL/6J and DBA/2J. Previous work has shown that animals of various C57BL substrains prefer a 10% ethanol solution to water in a two-bottle preference test, and that animals of various DBA/2 substrains avoid alcohol. In the present study, C57BL/6J mice were found to have 300% more aldehyde dehydrogenase activity than DBA/2J mice and 30% more alcohol dehydrogenase activity. The F₁ generation is intermediate to the parents in preference for the 10% alcohol solution and is also found to possess intermediate levels of alcohol and aldehyde dehydrogenase activity. These experiments suggest a systematic relationship between the behavioral trait of ethanol preference and the activity of aldehyde dehydrogenase and a similar but much less pronounced relationship with alcohol dehydrogenase.This research was supported by grant GM14547 from the National Institute of General Medical Sciences.     

Vascular extracellular adenosine metabolism in mice correlates with susceptibility to atherosclerosis

Abstract

Animal models are widely used in atherosclerosis research. The most useful, economic and valid is mouse genetic model of this pathology. Purinergic signaling is an important mechanism regulating processes involved in the vascular inflammation and atherosclerosis. The aim of this study was to measure vascular activities of nucleotide and adenosine-degrading ecto-enzymes in different strains of mice and to compare them to atherosclerotic susceptibility.

The vascular extracellular nucleotide catabolism pathway was analyzed in 6-month-old male genetically unmodified mouse strains: FVB/NJ, DBA/2J, BALB/c, C57Bl/6J and mouse knock-outs on C57Bl/6J background for LDLR (LDLR-/-) and for ApoE and LDLR (ApoE-/-LDLR-/-). LDLR-/- mice were a model of moderate hypercholesterolemia, while ApoE-/-LDLR-/- mice, a model of severe hypercholesterolemia with advanced atherosclerosis.

FVB/NJ, DBA/2J and BALB/c mice showed high rates of vascular extracellular AMP hydrolysis and low activity of adenosine deamination. In turn, all mice with the C57Bl/6J background expressed diminished activity of vascular AMP hydrolysis. Mice with genetically-induced hyperlipidemia and atherosclerosis on the C57Bl/6J background revealed increased ecto-adenosine deaminase activity.

Mouse strains that were resistant to atherosclerosis (FVB/NJ, DBA/2J, BALB/c) exhibited a protective extracellular vascular ecto-enzyme pattern directed toward the production of anti-inflammatory and anti-atherosclerotic adenosine. In turn, mice with genetically induced hypercholesterolemia and atherosclerosis expressed disturbed activities of ecto-5’nucleotidase and ecto-adenosine deaminase related to decreased production and increased degradation of extracellular adenosine.     

The alteration of attractiveness of intact males mice to females chemosignals, subjected of ionizing radiation in sublethal dose

After irradiation in a dose 4 Gy female mice of CBA and C57Bl/6 (female CBA during 18-23 days, female C57Bl/6 - 4-10 days) secretes with urine volatile components (chemosignals) which possess higher, than secretes intact females, attractiveness for intact males the same strains irrespective of a genotype. When estimation relative attractiveness postradiation secretes female mice CBA and C57Bl/6 intact males prefer chemosignals singenic (genetically identical) females during 1-23 day after irradiation. Observed olfactorial reaction male mice more differ from norm. In which males prefer chemosignals of allogenic (with a strange genotype) females. This disturbances identifed as postradiation reversion attractiving males of chemosignals, dependent on the genotype of females. Typical for norm chemosignalisation at females restored for 43 days after the irradiation. The mechanism and biological advisability of this phenomenon are discussed.     

Bacillary growth, interleukin 2 production defect, and specific antibody secretion governed by different genetical factors in mice infected subcutaneously with Mycobacterium lepraemurium

Different mouse strains were infected subcutaneously in the footpad with 10(7) Mycobacterium lepraemurium (MLM). At various stages of the infection, the number of acid-fast bacilli (AFB) in different organs, spleen cell interleukin 2 production, and specific IgM and IgG serum antibodies to MLM sonicate were assessed. Strains were separable into two distinct groups depending on the number of AFB recovered from the different organs, without any obvious influence of the Bcg gene. Thus C57BL/6, DBA/2, (C57BL/6 X DBA/2)F1 and C3H/Pas mice belonged to the high resistance group and DBA/1, BALB/c, and CBA strains to the low resistance group. Interleukin 2 production was depressed only in C57BL/6 and C3H/Pas mice. Anti-MLM antibody response also markedly varied according to strains, in terms of antibody titers, Ig class distribution, and species specificity, but with a different genetic pattern from that observed for MLM growth control.     

Use of genetic analysis to test the potential role of serotonin in alcohol preference.

The hypothesis that alcohol preference in mice is influenced by brain serotonin levels was tested using genetic analysis. Alcohol preference and static serotonin content were assessed in C57BL/Ibg (alcohol-preferring) and DBA/2 (alcohol-avoiding) mice, as well as in Fl and F2 generations obtained by crossbreeding. The two parental strains showed dissimilar alcohol preferences but identical concentrations of brain serotonin. Serotonin concentration segregated independently of alcohol preference in the F1 and F2 generations. These data provides strong evidence against the hypothesis that brain serotonin content influences alcohol preference. However, they do not preclude the possibility that differential alcohol influences on serotonin metabolism or turnover rate may result in differing preference for a alcohol.     

Syngeneic and allogeneic immunosupression effects of post-irradiation volatile excretions of mice

It was shown that immune and olfactory highly reactive CBA mice have reduced the ability to immune response in more extent under influence of volatile excretions of irradiated (4 Gy) singene mice, than allogene (C57Bl/6) mice. In lowreactive C57BL/6 mice deterioration of immune response also took place after influence of excretions of singene irradiated mice. There were no difference between the effects caused by excretions of intact and irradiated allogene (CBA) mice.