scholarly journals The Development of Strain Typical Defensive Patterns in the Play Fighting of Laboratory Rats

2014 ◽  
Vol 27 (3) ◽  
Author(s):  
Stephanie M. Himmler ◽  
Jena M. Lewis ◽  
Sergio M. Pellis
Keyword(s):  
Strain Difference ◽  
Strain Differences ◽  
Social Experiences ◽  
Sprague Dawley ◽  
Typical Pattern ◽  
Juvenile Period ◽  
Laboratory Rats ◽  
Play Fighting ◽  
Divergent Behavior ◽  
Early Juvenile Period

During play fighting, rats attack and defend the nape, which if contacted is nuzzled with the snout. While all strains of rats can use all defensive tactics to protect the nape, there are strain-typical preferences for using particular tactics This study tests two hypotheses for this strain difference: (1) that each strain has strain-specific thresholds for each tactic, or (2) that each strain attacks differently which leads to strain differences in which defense tactics are used. Juvenile Long-Evans and Sprague-Dawley males were tested with both unfamiliar (experiment 1) and familiar (experiment 2) same-strain and different-strain partners. Experiment two was conducted to determine if familiarity with a different strain might allow rats to modify their strain-typical pattern of play. If hypothesis (1) were true, they would maintain strain-typical defense patterns irrespective of partner strain, whereas for (2) it would vary with partner strain. Hypothesis (1) was supported in the first experiment; all the rats maintained their strain-typical patterns regardless of the partner’s strain. However, the second experiment supported neither hypothesis, as each animal displayed strain-divergent behavior when playing with partners of a different strain as well as with partners of the same strain. Given that in the second experiment subjects were reared in mixed-strain groups, it is possible that, during the early juvenile period, animals are susceptible to discordant social experiences

scholarly journals Domestication and the Role of Social Play on the Development of Sociocognitive Skills in Rats

2019 ◽  
Vol 32 ◽  
Author(s):  
Sergio M. Pellis ◽  
Vivien C. Pellis ◽  
Brett T. Himmler ◽  
Klaudia Modlinska ◽  
Rafał Stryjek ◽  
...  
Keyword(s):  
Cognitive Skills ◽  
Strain Differences ◽  
Juvenile Period ◽  
Play Fighting ◽  
Play Interactions ◽  
Wild Rat ◽  
Rearing Condition ◽  
Wild Rats ◽  
Long Evans

Several studies on rats and hamsters, across multiple laboratories, have shown that limiting play in the juvenile period leads to adults that have physiological and anatomical changes in the medial prefrontal cortex (mPFC) and reduced socio-cognitive skills. Peers raised with playful peers have better socio-cognitive skills than animals raised with adult partners. Using Long Evans hooded rats - a commonly used domesticated strain - this relationship has been replicated multiple times. However, when the same paradigm was used with laboratory-reared wild rats, no differences were found between rats reared with peers and ones reared with adults. It has been shown that the key play-generated experiences involved are those related to actively wrestling with a partner and turn taking (as measured by role reversals), which give both partners opportunity to gain the advantage during play fighting. In the present study, we tested the hypothesis that wild rat adults provide juveniles more such experiences than do adult Long Evans rats. The asymmetry in the play interactions in adult-juveniles pairs was compared between the two strains. As predicted, wild rat adults initiated more play with the juveniles, wrestled more and provided more opportunities for role reversals. The findings thus support the hypotheses for the observed strain differences in the effects of rearing condition on the mPFC.

Abstract P089: Assessment Of Sensorimotor Function To Establish A Clinically Relevant Animal Model Of Intracerebral Hemorrhage (ICH) Using The Hypertensive Transgenic Rat (mRen2)27

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Nicholas J Contillo ◽  
Anthony Anzalone ◽  
Nathan McMullen ◽  
Keyan Peterson ◽  
Christine Tschoe ◽  
...  
Keyword(s):  
Animal Model ◽  
Strong Predictor ◽  
Strain Difference ◽  
Strain Differences ◽  
Uncontrolled Hypertension ◽  
Transgenic Rat ◽  
Sprague Dawley ◽  
Relevant Animal Model ◽  
Inflammatory State ◽  
Poor Outcomes

Uncontrolled hypertension is the leading cause of spontaneous ICH and elevated SBP is a strong predictor of poor outcomes in ICH patients. An animal model of the chronically hypertensive, metabolically dysfunctional and pro-inflammatory state of the ICH patient population is needed to advance clinically-relevant ICH research. Transgenic (mRen2)27 rats overexpress the murine Ren2 gene and develop hypertension and metabolic syndrome by 12-14 weeks of age. Indices of diastolic and systolic cardiac function are in decline in (mRen2)27 males by 30 weeks of age, but are preserved in females at this age. To establish whether (mRen2)27 rats exhibit sensorimotor dysfunction as compared with control Sprague Dawley (SD) rats, male and female (mRen2)27 rats underwent corner turn (CT), vibrissae evoked forelimb placing (VEF), cage wire hang (CWH), and open-field (OF) testing for five consecutive weeks starting at 20-weeks of age (n=16; female=8; each strain). Despite the significant between-strain difference in SBP [189 ± 3 mmHg in (mRen2)27 and 119 ± 3 mmHg in SD; p<0.001], there were no significant between-strain differences in sensorimotor testing at weeks 20, 22, 23, and 24 (Table 1). At week 21, a significant between-strain difference was identified isolated to the VEF test (p<0.01). As sensorimotor testing is critical to assess the effect of experimentally-induced ICH in rodent models, the lack of strain differences supports the viability of (mRen2)27 rats as a clinically relevant model for the comparison of ICH superimposition in the two strains at this age without consistent baseline sensorimotor deficits. (Cardiovascular Sci. and Hypertension & Vasc. Res. Ctrs; Neurosurgery)

scholarly journals Ventilatory phenotypes among four strains of adult rats

2002 ◽  
Vol 93 (3) ◽  
pp. 974-983 ◽  
Author(s):  
Matthew R. Hodges ◽  
Hubert V. Forster ◽  
Paula E. Papanek ◽  
Melinda R. Dwinell ◽  
Genevieve E. Hogan
Keyword(s):  
Ventilatory Response ◽  
Strain Difference ◽  
Strain Differences ◽  
Inbred Strains ◽  
The Other ◽  
Brown Norway ◽  
Control Mechanisms ◽  
Sprague Dawley ◽  
Adult Rats ◽  
Different Strains

Our purpose in this study was to identify different ventilatory phenotypes among four different strains of rats. We examined 114 rats from three in-house, inbred strains and one outbred strain: Brown Norway (BN; n = 26), Dahl salt-sensitive ( n = 24), Fawn-hooded Hypertensive (FHH: n = 27), and outbred Sprague-Dawley rats (SD; n = 37). We measured eupneic (room air) breathing and the ventilatory responses to hypoxia (12% O2-88% N2), hypercapnia (7% CO2), and two levels of submaximal exercise. Primary strain differences were between BN and the other strains. BN rats had a relatively attenuated ventilatory response to CO2 ( P < 0.001), an accentuated ventilatory response to exercise ( P < 0.05), and an accentuated ventilatory roll-off during hypoxia ( P < 0.05). Ventilation during hypoxia was lower than other strains, but hyperventilation during hypoxia was equal to the other strains ( P > 0.05), indicating that the metabolic rate during hypoxia decreased more in BN rats than in other strains. Another strain difference was in the frequency and timing components of augmented breaths, where FHH rats frequently differed from the other strains, and the BN rats had the longest expiratory time of the augmented breaths (probably secondary to the blunted CO2 sensitivity). These strain differences not only provide insight into physiological mechanisms but also indicate traits (such as CO2 sensitivity) that are genetically regulated. Finally, the data establish a foundation for physiological genomic studies aimed at elucidating the genetics of these ventilatory control mechanisms.

scholarly journals Pinning in the Play Fighting of Rats: A Comparative Perspective With Methodological Recommendations

2016 ◽  
Vol 29 ◽  
Author(s):  
Stephanie M. Himmler ◽  
Brett T. Himmler ◽  
Rafał Stryjek ◽  
Klaudia Modlińska ◽  
Wojciech Pisula ◽  
...  
Keyword(s):  
Strain Differences ◽  
Competitive Interaction ◽  
The Other ◽  
Comparative Perspective ◽  
Sprague Dawley ◽  
Play Fighting ◽  
Sd Rats ◽  
Long Evans ◽  
Experimental Treatments ◽  
Pin Configuration

During play fighting, rats attack and defend the nape and during the course of this competitive interaction, they may adopt a configuration in which one animal stands over its supine partner (i.e., pin). Because the pin configuration is typically frequent and relatively easy to identify, it has been widely used as a marker to detect the effects of experimental treatments. In the present study, the frequency of pinning during standardized, 10min trials in three strains of rats, Long Evans hooded (LE), Sprague-Dawley (SD) and wild (WWCPS), was compared. LE and SD had higher rates than WWCPS rats (#/min: 6.5, 5.5, 1.5, respectively). When adjusted for strain differences in the frequency of attacks, SD as well as WWCPS rats had lower rates of pinning compared to LE rats. Both SD and WWCPS rats were less likely to use tactics of defense that promote pinning. Moreover, while the majority of the pins achieved in LE rats arose from the defender actively rolling over onto its back, the majority of pins in WWCPS rats arose because one partner pushed the other onto its back. SD rats were intermediate in this regard. Finally, once they do adopt the pin configuration, SD rats are less likely to remain supine than LE and WWCPS rats. That is, both SD and WWCPS rats have significantly fewer pins than LE rats, but a different combination of factors account for this. These data highlight the need to use a battery of measures for ascertaining the effects of experimental manipulations on play. Some suggested guidelines are provided.

Genetic strain differences in platelet aggregation and thrombus formation of laboratory rats

2007 ◽  
Vol 97 (04) ◽  
pp. 665-672 ◽  
Author(s):  
Hideki Ito ◽  
Hideki Hayashi ◽  
Yoshie Nagamura ◽  
Kazuyuki Toga ◽  
Yoshihisa Yamada ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Thrombus Formation ◽  
Strain Differences ◽  
Brown Norway ◽  
Sprague Dawley ◽  
Rat Strains ◽  
Laboratory Rats ◽  
Thrombosis Model ◽  
Considerable Strain

SummaryRats are employed to investigate the role of platelets in thrombus formation under flow conditions in vivo and to evaluate the pre-clinical potential of antiplatelet drugs. While Wistar and Sprague-Dawley (SD) strains are commonly used in thrombosis models, a number of rat strains have been established. Each strain possesses genetically unique characteristics such as hypertension, hyperglycemia or hyperlipidemia. The appropriate selection of a strain might have advantages for physiological and pharmacological studies. Comparative investigation of platelet aggregation among laboratory strains of rats is useful for the development of thrombosis models. In the present study, platelet aggregation response in eight laboratory rat strains, ACI, Brown Norway (BN), Donryu, Fischer 344 (F344), LEW, SD, Wistar and WKAH, were compared. Considerable strain differences were observed in ADP-, collagen- and TRAP-induced platelet aggregation. SD and BN are high-platelet-aggregation strains, while F344 and ACI are low-response strains. In the arteriovenous shunt thrombosis model, SD formed larger thrombi than F344 andWistar rats. In the FeCl 3 -induced thrombosis model with the carotid artery, the time to occlusion of SD was significantly shorter than of F344 and ACI rats. F344 and ACI rats had significantly increased bleeding times compared with SD rat. The present study demonstrates that there are considerable strain differences in platelet aggregation among laboratory rats, which reflect thrombus formation.

Acute renal denervation produces a diuresis and natriuresis in young SHR but not WKY rats

1986 ◽  
Vol 251 (4) ◽  
pp. F655-F661 ◽  
Author(s):  
M. A. Rudd ◽  
R. S. Grippo ◽  
W. J. Arendshorst
Keyword(s):  
Sodium Excretion ◽  
Renal Denervation ◽  
Strain Differences ◽  
Urine Flow ◽  
Sprague Dawley ◽  
Renal Vasculature ◽  
Renal Nerve ◽  
Water Excretion ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto

Clearance experiments were conducted to determine the effect of acute unilateral renal denervation (DNX) on renal hemodynamics and salt and water excretion in anesthetized 6-wk-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto genetic control rats (WKY). Before DNX, SHR had higher mean arterial pressure (33%) and renal vascular resistance (RVR) (57%) and lower glomerular filtration rate (GFR) (10%); urine flow and sodium excretion were similar. Following DNX in SHR, sodium and water excretion increased by 138 and 62%, respectively (P less than 0.001); GFR and RVR were unchanged. In contrast, DNX in WKY did not affect urine flow (0%) or sodium excretion (-21%). These strain differences were observed in Okamoto-Aoki rats from two sources. Effective DNX was indicated by 95% reduction of norepinephrine content 3 days after DNX in both strains. Six-week-old Sprague-Dawley and Munich-Wistar rats, in contrast to WKY, responded to DNX with a natriuresis (+182%) and diuresis (+95%) (P less than 0.001). Renal function was unaffected by sham DNX in SHR. Our results indicate that efferent renal nerve activity has little tonic influence on the renal vasculature in these young rats. Augmented neurotransmitter release and/or tubular responsiveness may be involved in fluid and electrolyte retention and the pathogenesis of hypertension in SHR. Conversely, blunted renal neuroeffector responses may prevent WKY from developing hypertension.

The Ecology of Juvenile Salmon in the Northeast Pacific Ocean: Regional Comparisons

2007 ◽  
Keyword(s):  
Pacific Ocean ◽  
Good Evidence ◽  
Juvenile Period ◽  
Physical Forcing ◽  
Northeast Pacific ◽  
Physical Environments ◽  
And Migration ◽  
The Times ◽  
Early Juvenile Period ◽  
Northeast Pacific Ocean

Abstract.—Research on the ecology of salmon in the northeast Pacific Ocean began in the early 20th century. Charles Gilbert and Willis Rich demonstrated the basis for the stock concept and were instrumental in changing common misconceptions of the times. Later in the 1900s, research endeavors, primarily under the auspices of the International North Pacific Fisheries Commission, led to important studies on the distribution and migration of maturing salmon on the high seas. Research on the early juvenile period was initiated later, especially after the 1982–1983 El Niño clearly showed the limits of the ocean’s carrying capacity along the west coast of the United States. There is now good evidence for both intra- and interspecific competition among salmon in the open ocean and for correlations between variable physical environments, such as El Niños and regime shifts, and survival of salmon during early ocean life. How mortality rates are affected by physical forcing, food availability, predation, and food web structure and how these effects will be modified by climate change and global warming are all major challenges for the future.

Strain difference in thermoregulation of rats surviving extreme heat

1982 ◽  
Vol 52 (2) ◽  
pp. 410-415 ◽  
Author(s):  
F. Furuyama
Keyword(s):  
Body Temperature ◽  
Heat Tolerance ◽  
Strain Difference ◽  
Body Weight Loss ◽  
The Body ◽  
Sprague Dawley ◽  
Survival Times ◽  
Sprague Dawley Rats ◽  
Thermoregulatory System ◽  
Different Strains

The survival times of unanesthetized rats in 42.5 degree C. 48% rh were studied in 12 different strains. In males, Sprague-Dawley rats (P less than 0.01) and Fisher 344/MK (P less than 0.05) showed significantly higher heat tolerance than the other 9 strains. Among Sprague-Dawley rats, females tolerated heat longer than males (P less than 0.05). There was no difference in lethal body temperature according to strains and exposure temperatures (38.5–48.5 degree C). Maximum survivable body temperature was 43.1 degree C in males and 43.3 degree C in females. The body weight loss in heat was greater in Sprague-Dawley, Fisher 344/MK, and JCL:Wistar strains. The degree of saliva spreading during the equilibrium period just below the maximum survivable body temperature correlated significantly with heat tolerance and was found to be the index of strain difference in heat tolerance. These findings demonstrated that the thermoregulatory system of rats is controlled genetically, though survival times of individuals in different strains sometimes overlap.

Regulation mode of evaporative cooling underlying a strategy of the heat-tolerant FOK rat for enduring ambient heat

2003 ◽  
Vol 285 (6) ◽  
pp. R1439-R1445 ◽  
Author(s):  
Fujiya Furuyama ◽  
Masataka Murakami ◽  
Etsuro Tanaka ◽  
Hideki Hida ◽  
Daisuke Miyazawa ◽  
...  
Keyword(s):  
Heat Tolerance ◽  
Strain Difference ◽  
Strain Differences ◽  
Ambient Temperatures ◽  
Saliva Secretion ◽  
Wide Range ◽  
Heat Tolerant ◽  
Hot Environments ◽  
Regulation Mode

Compared with other rat strains, the inbred FOK rat is extremely heat tolerant. This increased heat tolerance is due largely to the animal's enhanced saliva spreading abilities. The aims of the present study were to 1) quantify the heat tolerance capacity of FOK rats and 2) determine the regulatory mode of the enhanced salivary cooling in these animals. Various strains of rats were acutely exposed to heat. In the heat-intolerant strains, saliva spreading was insufficient and the core temperature (Tc) rose rapidly. In contrast, FOK rats maintained an elevated Tc plateau (39.5 ± 0.7°C) for 5-6 h over a wide range of ambient temperatures (Ta) (37.5-42.5°C). In hot environments the FOK rats secreted copious amounts of saliva and spread it over more than the entire ventral body surface. FOK rats had a low Tc threshold for salivation, and the salivation rate increased linearly in proportion to the Tc deviation from the threshold. No strain difference or temperature effect was observed in the saliva secretion rate from in vitro submandibular glands perfused by sufficient doses of ACh. These results suggest that 1) the ability of FOK rats to maintain a moderate steady-state hyperthermia (39.5 ± 0.7°C) over a wide Ta range is enabled by a lowered threshold Tc for salivation and functional negative-feedback control of saliva secretion and 2) strain differences in ability to endure heat stress are mainly attributable to changes in the thermoregulatory control system rather than altered secretory abilities of the salivary glands.

Strain Differences Occurring in an Experimental Study of Punishment

1965 ◽  
Vol 16 (2) ◽  
pp. 531-536 ◽  
Author(s):  
Morton H. Kleban
Keyword(s):  
Experimental Study ◽  
Empirical Evidence ◽  
Wistar Rats ◽  
Strain Differences ◽  
Training Procedure ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Y Maze ◽  
Minimum Number ◽  
The Difference

Forty-three Sprague-Dawley and 43 Wistar rats were given reward training for 40 trials in a Y-maze. On the next 20 trials, control groups were continued under the same training procedure, and 50% shock trials were introduced in the training of the remaining rats. For the extinction training, the reward was shifted to the opposite arm and 50% shock was continued for the no-delay and 30-sec. delay shock groups. The most significant results were that in the 30-sec. delay groups, the delay helped the Sprague-Dawley rats reverse in a minimum number of trials, whereas the Wistar rats showed strong indications of response stereotypy. The findings with respect to the Sprague-Dawley rats supported the empirical evidence on the effectiveness of delay in overcoming response persistence and the findings on the Wistar rats supported the empirical evidence on omission in punishment. The difference in response to punishment between the two albino strains emphasizes the need for experimental study of strain factors. Experiments should be repeated with several animal strains to remedy over-generalization from single strains and to help elaborate our understanding of the interaction present between punishment and strains.

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