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At least 19 recordsLinked to original sources

Genetic control of susceptibility to autologous immune complex glomerulonephritis in inbred rat strains.

Twelve inbred rat strains were tested for their susceptibility to autologous immune complex glomerulonephritis (AIC) after a single injection of a primary tubular epithelial fraction emulsified in Freund's complete adjuvant. Six strains (Lewis, AS, BDV, L.BDV, AS2, L.AS2) showed high responsiveness in terms of proteinuria and immunohistological changes, which could be observed after 3 months. Strains BN, AVN and DA were completely resistant, even after 6 months of observation. An additional adjuvant (pertussis vaccine) did not break non-responsiveness in one of these strains (BN). Strains which share the Lewis strain genetic background (L.BN, L.AVN and L.WP) seemed to be at least weakly susceptible to AIC. A close association between susceptibility and the major histocompatibility haplotypes is demonstrated in segregation studies involving Lewis, L.BN and BN rats. A threshold model of AIC susceptibility, based on the action of major histocompatibility-linked genes and background genes, is suggested.

Animals↗

Renal dopamine-1 receptors in hypertensive inbred rat strains with and without hyperactivity.

Renal dopamine-1 (DA-1) receptors are involved in the regulation of sodium transport in several nephron segments, including the proximal convoluted tubule (PCT). DA-1 receptors in the PCT and cortical collecting duct of normotensive rats are linked to the stimulation of adenylyl cyclase (AC). We have reported a defect in the DA-1 receptor/AC coupling in the PCT of the spontaneously hypertensive rat (SHR) of the Okamoto-Aoki strain. Hyperactivity and hypertension are both expressed in the SHR. To determine if the DA-1 receptor coupling defect is associated with hyperactivity or hypertension, we studied the DA-1 receptor in the PCT of two new inbred rat strains derived from the SHR: the hyperactive WKHA and the hypertensive WKHT rat. Tail-cuff blood pressures taken at 4 weeks indicated that WKHT rats were not hypertensive (86 +/- 3 mm Hg, n = 6), whereas at 12 weeks systolic pressures in both SHR and WKHT rats exceeded 150 mm Hg. Hyperactivity, however, was noted in WKHA rats even at this early age. Basal AC activity was similar in WKHA and WKHT PCT in either age group. In the older rats, the DA-1 agonist fenoldopam (10(-7) mol/L) stimulated AC activity in WKHA (70.6 +/- 16.1 fmol per 3 mm PCT per 20 minutes, n = 3) but not in WKHT PCT (43.3 +/- 5.3 fmol per 3 mm PCT per 20 minutes, n = 4). Gpp(NH)p (10(-5) mol/L), a nonhydrolyzable GTP analogue, stimulated AC activity to a similar extent in WKHA and WKHT PCT.(ABSTRACT TRUNCATED AT 250 WORDS)

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

Comparison of microsomal drug-metabolizing enzymes in 14 rat inbred strains.

Drug metabolic capacity in liver microsomes of 14 rat inbred strains was investigated. Cytochrome P-450 content as well as the following enzyme activities were measured: NADPH cyt. c(P-450) reductase (Red.), aminopyrine N-demethylase (APDM), ethoxycoumarin O-deethylase (ECOD), 1-naphthol: UDP-glucuronosyltransferase (NGT) and hydrolysis of acetylsalicylic acid (ASA; measured at pH 5.5 and pH 7.4). All enzymes measured were found to exhibit statistically significant inter-strain differences. In males the enzyme activities varied over a 7.3-fold (ECOD) to 1.4-fold (cytochrome P-450) range. Other inter-strain differences were generally larger than 2-fold: ASA-hydrolysis at pH 5.5 and 7.4 (3.9- and 3.3-fold variation, respectively), NGT and Red. (2.1-fold variation) and APDM (1.8-fold variation). In females similar, but somewhat smaller inter-strain differences were observed. Correlations between different enzyme activities were generally poor (correlation coefficients r less than 0.7). An exception was the correlation between ASA-hydrolysis at pH 5.5 and pH 7.4 (r = 0.79). We conclude that ASA hydrolysis at pH 5.5 and 7.4 is mediated by the same enzyme or by coregulated enzymes and that all other activities are mediated by different or differentially regulated enzymes. Based on analysis of variance and subsequent inter-strain comparisons, all strains appear to express a unique profile of liver microsomal drug metabolism. No two strains are identical with respect to all activities measured. We suggest that differences between inbred rat strains and particularly the difference in balance between different enzymes in various strains can be used advantageously in pharmacological and toxicological experiments.

Analysis of Variance↗

A multiple-test study of anxiety-related behaviours in six inbred rat strains.

Recent studies have underlined the impact of genetic factors in anxiety profiles. In this context, we have initiated a series of experiments aiming to select, among six inbred strains of rats, a pair of strains that contrasts the most in fear-related behaviours measured in the open field, the elevated plus-maze, the black and white box and the social interaction test. Significant interstrain differences were found for all behavioural measures. A factor analysis of all variables produced three independent factors explaining 85.1% of the total variance. Factor 1 had high loadings from variables related to the approach/avoidance towards aversive stimuli (e.g., center of the open field, open arms of the plus-maze and white compartment of the black/white box). Variables related to general activity in novel environments (e.g., total locomotion in the open field and closed-arm entries in the plus-maze) loaded highly on Factor 2. Defecation and time of social interaction loaded positively on Factor 3. To verify whether elevated plus-maze variables loading on Factor 1 were associated to anxiety, the effects of single doses of diazepam and pentylenetetrazole were examined in Lewis and SHR rats, i.e., the most contrasting strains regarding Factor 1. Variables with high loadings on this factor changed in opposite ways in response to diazepam and pentylenetetrazole treatments. This study suggests, thus, that Lewis and SHR strains may constitute a useful model for studying the neurobiological mechanisms underlying the interindividual differences in baseline levels of anxiety.

Animals↗

N-acetylation of aromatic amines: genetic polymorphism in inbred rat strains.

The inheritance of rat liver N-acetyltransferase polymorphism was investigated with reciprocal genetic crosses between slow (NSD/N) and rapid (Peth/N) acetylator strains. Rat liver N-acetyltransferase activity was determined using a spectrophotometric assay which measured the amount of arylamine substrate present after incubation with N-acetyltransferase in vitro. Male N-acetyltransferase activities assayed in liver preparations using p-aminobenzoic acid and p-toluidine as substrates indicate bimodality of the parental strains and unimodality of the F-1 generation; limited data suggest trimodality (not significantly different from a 1:2:1 ratio) of the F-2 generation. Reciprocal crosses of WKY/N, another slow acetylator strain, and the Peth/N strain gave results similar to those of the NSD/N x Peth/N cross. Female N-acetyltransferase activities in all strains studied were lower than male N-acetyltransferase activities, but were similarly distributed in the parental and F-1 generations. The male/female N-acetyltransferase activity ratio was substrate- and genotype-dependent. Results show that regulation of the variation of rat liver N-acetyltransferase activity is consistent with autosomal Mendelian inheritance of two major alleles at a single gene locus.

4-Aminobenzoic Acid↗

[Evaluation of the antigenicity of heart valve leaflets using inbred rat strain combinations (author's transl)].

Experiments with large, non-inbred animals yield no reliable evidence in the antigenicity of heart valves. With inbred strains of rats, however, it is possible to obtain evidence on the immunological reactions of heart valve leaflet transplants. Our experiments were undertaken on the inbred rat strains (CDR, LEW, CAP and BD5, using combinations as follows: syngeneic strain combination (CDF leads to CDF), weakly allogenic (RtH-1-identical) strain cimbination (LEW leads to CDF), strongly allogeneic (RtH-1-incompatible) strain combination (CAP leads to CDF). Strain BD5 was used for the control skin grafts. Either one or two heart valve leaflets were heterotopically intra-aortally transplanted. Sensitization was verified humorally by transplantation antibody titers and cellularly by subsequent donorspecific skin transplants. The following results were achieved: Allogeneic heart valve leaflets are antigenic. Intravascular grafting of one heart valve leaflet induces the same degree of sensitization as the grafting of two leaflets. In the RtH-1-identical system, sensitization is revealed only by subsequent skin grafting, whereas in the RtH-1-incompatible system, sensitization is humorally demonstrated as well. This indicates that in heart valve leaflet transplantation cellmediated reactivity is a more sensitive indicator than the humoral one. The greater the immunological difference is, the clearer the sensitization will be. In the strongly allogeneic system, the sensitization is even demonstrated humorally; skin grafts are rejected as "white grafts". Improved long-term results may be expected in allogeneic vital heart valve transplants if consideration is given to the HLA compatibility between donor and recipient; the appearance of delayed insufficiency could be greatly lessened or even deferred.

Animals↗

Forced swimming behavior is not related to the corticosterone levels achieved in the test: a study with four inbred rat strains.

The behavior of four inbred strains of rats in the holeboard and the forced swimming tests, and its relationship with a physiological index of stress (serum corticosterone) were studied in adult male rats. The strains were: Fisher 344 (FIS), Lewis (LEW), Spontaneously hypertensive (SHR), and Wistar-Kyoto (WKY). In the holeboard, SHR rats were the most active and WKY the less active, the other strains showing intermediate levels of activity. During the first exposure to forced swimming WKY were far more passive than the other three strains and the same was observed during the second exposure. When corticosterone levels after this second exposure to water was determined, LEW rats showed lower values than the other three strains. Therefore, no apparent relationship between behavior and stress-induced corticosterone secretion exists. Although a single point measurement of only on physiological index of stress has important limitations, the present data do not give support to a strong relationship between the behavior of the animals in the forced swimming test and emotional reactivity to stress. It is therefore possible that forced swimming behavior might not be mainly a panic-like reaction, but the result of the tendency of the animals to adopt passive strategies in inescapable situations. Although more studies are needed to firmly establish this assumption, WKY rats might be, at least potentially, a useful model of depressive-like behavior.

Animals↗

Identification of inbred rat strains by using DNA fingerprinting method.

DNA fingerprinting method was applied to identify inbred strains of laboratory rats. By Southern blot hybridization with core sequence of minisatellite DNA as a probe, typical hypervariable patterns of DNA fingerprint were obtained in inbred rat strains. The patterns were completely different among 15 rat strains examined, and the patterns of the DNA fingerprint of samples obtained from the same strain were completely identical. The patterns of the DNA fingerprint of two substrains derived from the same strain were identical, indicating relative stability of the patterns over a large number of generations. Therefore, we concluded that the DNA fingerprinting method was useful for the identification of inbred strains in genetic monitoring of laboratory rats.

Animals↗

Tracheal transplantation. III. Demonstration of transplantation antigens on the tracheal mucosa of inbred rat strains.

Tracheal transplants were performed on inbred strains of rats. Monoclonal antibodies were used in combination with the biotin-avidin technique for demonstrating donor-specific RT1 Ac transplantation antigen. Transplantation antigens were predominantly contained in the tracheal mucosal cells. No donor-specific antigens could be found in the mucosa of transplants which survived orthotopic tracheal transplantation for longer than 210 days. This suggests that the mucosa of the transplant is rejected and replaced by a mucosa from the recipient.

Animals↗

Animal modelling of human polymorphic drug oxidation--the metabolism of debrisoquine and phenacetin in rat inbred strains.

The metabolism of debrisoquine (5 mg kg-1 orally) was investigated in females of 7 strains of rat. Two major metabolic pathways, those of 4- and 6-hydroxylation were found to be polymorphic. The DA strain eliminated in urine only 7-10% of the dose as 4-hydroxy-debrisoquine together with 31-55% debrisoquine while the corresponding values for the Lewis strain were 44-55% and 11-17% respectively. Accordingly, DA and Lewis rats were proposed as models for the human PM (poor metabolizer) and EM (extensive metabolizer) drug oxidation phenotypes. To further test this model, DA and Lewis rats were given phenacetin (200 mg kg-1 orally). This underwent O-de-ethylation to paracetamol (52-55%) and aromatic 2-hydroxylation (7-8%) in Lewis rats. The corresponding findings in DA rats were 35-40% O-de-ethylation and 12-13% 2-hydroxylation. It is suggested that, with respect to both debrisoquine and phenacetin, Lewis and DA inbred rat strains afford a model of oxidative drug metabolism for the human EM and PM phenotypes respectively.

Animals↗

Genetic profiles of 12 inbred rat strains for 46 microsatellite loci selected as genetic monitoring markers.

Genetic profiles for 46 microsatellite loci of 12 inbred strains of rats, including 2 congenic strains and a coisogenic strain, have been demonstrated. Rates of loci with different alleles between 2 inbred strains, which are not closely related to each other in origin, were from 71.7% between ACI/N and IS/Kyo strains to 41.3% between F344/N and TM/Kyo. On the other hand, the rates were 0% in both of 2 sets of congenic strains; between F344/N and F344/N-rnu, or between BN/fMaiKyo and BN.IS. When WTC/Kyo and the coisogenic strain TRM/Kyo (WTC/Kyo-tm) were compared for 115 microsatellite loci, no loci with different alleles between the strains were found. The 46 loci should be useful as genetic monitoring markers, since all of the primer pairs generate distinct PCR-products at a fixed annealing temperature of 55 degrees C.

Alleles↗

Differential establishment and maintenance of oral ethanol reinforced behavior in Lewis and Fischer 344 inbred rat strains.

Oral ethanol self-administration was investigated systematically in two inbred strains of rats, Fischer 344 CDF (F-344)/CRLBR (F344) and Lewis LEW/CRLBR (LEW). For both strains ethanol maintained higher response rates and was consumed in larger volumes than the water vehicle. In addition, blood ethanol levels increased with increases in ethanol concentration. However, LEW rats drank substantially more ethanol than F344 rats. The typical inverted U-shaped function between ethanol concentration and number of deliveries was observed for the LEW rats, whereas for the F344 rats much smaller differences were seen between ethanol and water maintained responding. For the LEW strain, as the fixed-ratio size was increased, the number of responses increased almost in direct proportion to the fixed-ratio size increase, so that at least at the lower fixed-ratio values the rats were obtaining similar numbers of deliveries at different fixed-ratio sizes. However, a decrease in ethanol deliveries and blood ethanol levels was observed at higher fixed-ratio sizes. Similar results were obtained in F344 rats, but the amount of responding was lower and less consistent. LEW rats showed significantly higher response rates, numbers of ethanol deliveries and blood ethanol levels. Ethanol-induced behavioral activation also was observed in LEW rats, but not in F344 rats. These results support the conclusion that ethanol serves as a strong positive reinforcer for LEW rats and as a weak positive reinforcer for F344 rats, and that genotype is a determinant of the degree to which ethanol functions as a reinforcer.

Animals↗

Phenotypic variation in sensorimotor performance among eleven inbred rat strains.

As a first step toward identifying the genes that determine sensorimotor ability (motor coordination) we subjected 11 inbred strains of rats to three different tests for this trait. Rats were tested at 13 wk of age to determine how long they could remain on 1) a rotating cylinder as the velocity of rotation increased every 5 s (1-direction rotation test), 2) a rotating cylinder that reversed direction every 5 s and increased velocity every 10 s (2-direction rotation test), and 3) a platform that was tilted 2 degrees every 5 s from 22 to 47 degrees (tilt test). On all three tests, rats of the PVG strain demonstrated the greatest sensorimotor ability. In contrast, rats of the MNS strain were most often represented among the group of strains that demonstrated the lowest performance on all tests. Considering all three tests, there was a 3- to 13-fold range in sensorimotor performance between the highest and lowest strains. This large divergence between the highest and lowest strains provides a genetic model that can be used to identify intermediate phenotypes and quantitative trait loci that contribute to sensorimotor ability.

Animals↗

Susceptibility of inbred rat strains to experimental thyroiditis: quantitation of thyroglobulin-binding cells and assessment of T-cell function in susceptible and non-susceptible strains.

Ten inbred strains of rats were immunized with crude homologous thyroglobulin emulsified in Freund's complete adjuvant in order to investigate strain susceptibility to the induction of both thyroiditis and antibody to thyroglobulin. Two strains (LH and AUG) were found to be extremely susceptible and had 100% incidence of thyroid lesions which in general varied from moderate to very severe (mean index of pathology+/-SE, 2-5+/-0-2 and 2-1+/-0-4 respectively). One other strain (HL) also had 100% incidence of lesions but there were consistently mild in character (1-1+/-0-1). Two strains (DA and SD) were variable, with thyroid change varying from negative to severe. Three strains (LEW, WAG and PVG/c) had occasional lesions and the remaining two strains (AS and CAM) showed no thyroid change. Four strains (LH, AUG, HL and DA) consistently produced good antibody responses to thyroglobulin (mean titres+/-SE 7-3+/-0-3, 9-5+/-0-4, 6-9+/-0-3 and 6-6+/-0-5 respectively). In contrast WAG and CAM rats failed to develop autoantibody and the responses of AS, PVG/c and SD strain rats were quite variable. Although the autoantibody response generally correlated well with the presence of thyroiditis in a particular strain, LEW, AS and PVG/c rats often had good antibody levels with minimal thyroid lesions. Females of the most susceptible strains (LH and AUG) were found to have significantly more severe thyroid lesions and higher antibody titres to thyroglobulin than males. The most susceptible strains were all found to be of the Ag-B5 major histocompatibility genotype whilst the least susceptible were of the Ag-B2 genotype. However, wide interstrain variability was noted within the Ag-B5 genotype particularly with respect to the induction and extent of thyroid lesions. It was not found possible to relate the divergence in susceptibility between rat strains of Ag-B5 and Ag-B2 genotypes to differences in respective numbers of thyroglobulin-binding cells within the circulation of the non-immunized animal. Similarly, there were no differences in response between a susceptible (LH) and non-susceptible (CAM) strain to the phytomitogens PHA and Con A.

Animals↗

Behavioral reactivity to social and nonsocial stimulations: a multivariate analysis of six inbred rat strains.

Male rats from six inbred rat strains (Spontaneously Hypertensive Rat, Wistar Kyoto, Brown Norway, Wistar Furth, Fischer 344, and Lewis) have been compared for their behavioral reactivity when placed in several nonsocial (elevated plus-maze, open field) and social (social interaction in aversive and neutral environment, resident-intruder test, chronic social stress) settings. In addition, a factorial analysis was performed to assess how the variables measured in these different tests related to each other. Besides significant strain-related differences in all tests, the factorial analysis showed that, in nonsocial environments, the strains contrasted essentially along two independent behavioral traits, the propensity to approach or avoid an aversive stimulus and general motor activity in novel environments (two indices of emotionality). In the social settings, marked interstrain differences were observed regarding the expression of aggressive behaviors but these differences were not related to the respective levels on the two nonsocial components of reactivity. Furthermore, large genetic differences were observed in variations of body weight induced by a chronic social stressor paradigm. The factorial analysis suggested a lack of relationship between the effect of social stressors on body weight and the measures of emotionality and general activity obtained in the nonsocial tests. Conversely, these variations were influenced by the levels of aggressiveness and sociability. Taken together, these results show (i) that the behavioral variability observed in rats in social and nonsocial environments, is influenced by genetic factors and (ii) that the behavioral reactivity to social stimulations is a specific feature, dissociable from the levels of the different components of emotionality (approach/avoidance and general activity) as evaluated by the behavioral responses to nonsocial settings.

Aggression↗