Environmental enrichment of young adult rats (Rattus norvegicus) in different sensory modalities has long-lasting effects on their ability to learn via specific sensory channels.

2017 ◽  
Vol 131 (2) ◽  
pp. 79-88 ◽  
Author(s):  
Vassilissa Dolivo ◽  
Michael Taborsky
Keyword(s):  
Young Adult ◽  
Rattus Norvegicus ◽  
Environmental Enrichment ◽  
Adult Rats ◽  
Sensory Modalities

scholarly journals Short-term but not long-term exposure to an enriched environment reduces unconditioned fear responses but not conditioned fear responses

2019 ◽  
Vol 12 (5) ◽  
pp. 86
Author(s):  
K. M. H. Cavalcante
Keyword(s):  
Young Adult ◽  
Environmental Enrichment ◽  
Conditioned Fear ◽  
Enriched Environment ◽  
Spatial Learning And Memory ◽  
Emotional States ◽  
Short Term ◽  
Adult Rats ◽  
Electrical Shock ◽  
Beneficial Effects

Environmental enrichment (EE) has been shown to produce beneficial effects in animal models of a wide variety of neurological and psychiatric disorders. EE exhibits antidepressant function; reduces anxiety, improves spatial learning and memory impairment. EE can reduce sensitivity to loss of reward by reducing frustration-like emotional states and facilitates the extinction of conditioned fear. However, some studies related to the emotional effects of EE present controversial results such as reduction or increase in anxiety. The time of exposure to an enriched environment seems to be an important factor in the behavioral responses presented by animals subjected to aversive stimuli. The present study compared the effects of two and four week exposure to EE with young adult Wistar rats under the same conditions and protocol on fear behavioral parameters in the face of footshock (unconditioned fear) and on re-exposure to an environment after electrical shock pairing (conditioned fear). We showed that the EE with a duration of two weeks reduced the freezing response of the animals in an unconditioned fear situation, that is, with the aversive stimulus present in the environment, however, did not influence the same behavior in a conditioned fear situation. In addition, the short-term EE developed the locomotor and exploratory activity, identified by the high rearing behavior, which may also suggest a low level of anxiety in these animals. We can conclude that EE changes the unconditioned fear responses of young adult rats. In addition, the duration of EE interferes differently, being two weeks of treatment with EE sufficient to cause improvement in coping with unconditioned aversive situations. We suggest that the emotional benefits resulting from the welfare provided by EE can be abolished by the longer duration of this treatment, due to the already known effect of tolerance to lasting or abundant rewards.

scholarly journals Hypertension in Prenatally Undernourished Young-Adult Rats Is Maintained by Tonic Reciprocal Paraventricular–Coerulear Excitatory Interactions

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3568
Author(s):  
Bernardita Cayupe ◽  
Carlos Morgan ◽  
Gustavo Puentes ◽  
Luis Valladares ◽  
Héctor Burgos ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Young Adult ◽  
Binding Sites ◽  
Systolic Pressure ◽  
Adult Rats ◽  
Excitatory Pathways ◽  
Induced Hypertension ◽  
Prenatal Undernutrition ◽  
Number Of Cells

Prenatally malnourished rats develop hypertension in adulthood, in part through increased α1-adrenoceptor-mediated outflow from the paraventricular nucleus (PVN) to the sympathetic system. We studied whether both α1-adrenoceptor-mediated noradrenergic excitatory pathways from the locus coeruleus (LC) to the PVN and their reciprocal excitatory CRFergic connections contribute to prenatal undernutrition-induced hypertension. For that purpose, we microinjected either α1-adrenoceptor or CRH receptor agonists and/or antagonists in the PVN or the LC, respectively. We also determined the α1-adrenoceptor density in whole hypothalamus and the expression levels of α1A-adrenoceptor mRNA in the PVN. The results showed that: (i) agonists microinjection increased systolic blood pressure and heart rate in normotensive eutrophic rats, but not in prenatally malnourished subjects; (ii) antagonists microinjection reduced hypertension and tachycardia in undernourished rats, but not in eutrophic controls; (iii) in undernourished animals, antagonist administration to one nuclei allowed the agonists recover full efficacy in the complementary nucleus, inducing hypertension and tachycardia; (iv) early undernutrition did not modify the number of α1-adrenoceptor binding sites in hypothalamus, but reduced the number of cells expressing α1A-adrenoceptor mRNA in the PVN. These results support the hypothesis that systolic pressure and heart rate are increased by tonic reciprocal paraventricular–coerulear excitatory interactions in prenatally undernourished young-adult rats.

scholarly journals Stimulus-specific adaptation in auditory thalamus of young and aged awake rats

2013 ◽  
Vol 110 (8) ◽  
pp. 1892-1902 ◽  
Author(s):  
Ben D. Richardson ◽  
Kenneth E. Hancock ◽  
Donald M. Caspary
Keyword(s):  
Young Adult ◽  
Auditory Cortex ◽  
Brown Norway ◽  
Oddball Paradigm ◽  
Adult Rats ◽  
Specific Adaptation ◽  
Auditory Thalamus ◽  
Gating Mechanism ◽  
Medial Geniculate ◽  
Awake Rats

Novel stimulus detection by single neurons in the auditory system, known as stimulus-specific adaptation (SSA), appears to function as a real-time filtering/gating mechanism in processing acoustic information. Particular stimulus paradigms allowing for quantification of a neuron's ability to detect novel or deviant stimuli have been used to examine SSA in the inferior colliculus, medial geniculate body (MGB), and auditory cortex of anesthetized rodents. However, the study of SSA in awake animals is limited to auditory cortex. The present study used individually advanceable tetrodes to record single-unit responses from auditory thalamus (MGB) of awake young adult and aged Fischer Brown Norway (FBN) rats to 1) examine the presence of SSA in the MGB of awake rats and 2) determine whether SSA is altered by aging in MGB. MGB single units in awake FBN rats displayed SSA in response to two stimulus paradigms: the oddball paradigm and a random blocked/interleaved presentation of a set of frequencies. SSA levels were modestly, but nonsignificantly, increased in the nonlemniscal regions of the MGB and at lower stimulus intensities, where 27 of 57 (47%) young adult MGB units displayed SSA. The present findings provide the initial description of SSA in the MGB of awake rats and support SSA as being qualitatively independent of arousal level or anesthetized state. Finally, contrary to previous studies in auditory cortex of anesthetized rats, MGB units in aged rats showed SSA levels indistinguishable from SSA levels in young adult rats, suggesting that SSA in MGB was not impacted by aging in an awake preparation.

scholarly journals Differential effects of targeted tongue exercise and treadmill running on aging tongue muscle structure and contractile properties

2013 ◽  
Vol 114 (4) ◽  
pp. 472-481 ◽  
Author(s):  
Heidi Kletzien ◽  
John A. Russell ◽  
Glen E. Leverson ◽  
Nadine P. Connor
Keyword(s):  
Young Adult ◽  
Exercise Group ◽  
Contractile Properties ◽  
Treadmill Running ◽  
Brown Norway ◽  
Middle Aged ◽  
Adult Rats ◽  
Tongue Muscle ◽  
Muscle Structure ◽  
Old Rats

Age-associated changes in tongue muscle structure and strength may contribute to dysphagia in elderly people. Tongue exercise is a current treatment option. We hypothesized that targeted tongue exercise and nontargeted exercise that activates tongue muscles as a consequence of increased respiratory drive, such as treadmill running, are associated with different patterns of tongue muscle contraction and genioglossus (GG) muscle biochemistry. Thirty-one young adult, 34 middle-aged, and 37 old Fischer 344/Brown Norway rats received either targeted tongue exercise, treadmill running, or no exercise (5 days/wk for 8 wk). Protrusive tongue muscle contractile properties and myosin heavy chain (MHC) composition in the GG were examined at the end of 8 wk across groups. Significant age effects were found for maximal twitch and tetanic tension (greatest in young adult rats), MHCIIb (highest proportion in young adult rats), MHCIIx (highest proportion in middle-aged and old rats), and MHCI (highest proportion in old rats). The targeted tongue exercise group had the greatest maximal twitch tension and the highest proportion of MHCI. The treadmill running group had the shortest half-decay time, the lowest proportion of MHCIIa, and the highest proportion of MHCIIb. Fatigue was significantly less in the young adult treadmill running group and the old targeted tongue exercise group than in other groups. Thus, tongue muscle structure and contractile properties were affected by both targeted tongue exercise and treadmill running, but in different ways. Studies geared toward optimizing dose and manner of providing targeted and generalized tongue exercise may lead to alternative tongue exercise delivery strategies.

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