Paper or Plastic? Exploring the Effects of Natural Enrichment on Behavioural and Neuroendocrine Responses in Long-Evans Rats

2016 ◽  
Vol 28 (5) ◽  
Author(s):  
M. Bardi ◽  
C. Kaufman ◽  
C. Franssen ◽  
M. M. Hyer ◽  
A. Rzucidlo ◽  
...  
1980 ◽  
Vol 48 (6) ◽  
pp. 927-932 ◽  
Author(s):  
S. T. Lu ◽  
N. Lebda ◽  
S. Pettit ◽  
S. M. Michaelson

One hundred and eighteen male rats (Long-Evans) were acclimated to experimental procedures (i.e., handling, transferring from and back to "home" cage, body weight and colonic temperature determinations) for 2 wk and then subjected to cage confinement for 3 days before microwave (MW) exposure to 2,450 MHz for 1-, h, at 1-70 mW.cm-2 or sham exposure at ambient temperature of 24 +/- 1 degree C. Colonic temperature increased after exposure to power densities greater than or equal to 20 mW.cm-2 and was the most sensitive parameter measured. Inverse relationships between corticosterone and thyrotropin or growth hormone were noted after exposure for 1 h at 50 mW.cm-2 and above. Pituitary-thyroid function was inhibited after exposure to 20 mW.cm-2 for 2-8 h. Changes in other hormones were transient or inconsistent. Corticosterone, thyrotropin, and growth hormone levels could be correlated with power density or colonic temperature in rats exposed to MW for 1 h; corticosterone and thyrotropin levles correlated with colonic temperatures in shams. Body temperature influences adenohypophysial hormones in studies of MW biological effects.


Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs

Investigation of the spontaneous pituitary adenomas in rat have been limited mainly to light microscopic study. Furth et al. (1973) described them as chromophobic, secreting prolactin. Kovacs et al. (1977) in an ul trastructural investigation of adenomas of old female Long-Evans rats, found that they were composed of prolactin cells. Berkvens et al. (1980) using immunocytochemistry at the light microscopic level, demonstrated that some spontaneous tumors of old Wistar rats could contain GH, TSH or ACTH as well as PRL.


Author(s):  
I.C. Murray

In women, hyperprolactinemia is often due to a prolactin (PRL)-secreting adenoma or PRL cell hyperplasia. RRL excess stimulates the mammary glands and causes proliferation of the alveolar epithelium. Bromocriptine, a dopamine agonist, inhibits PRL secretion and is given to women to treat nonpuerperal galactorrhea. Old female rats have been reported to have PRL cell hyperplasia or adenoma leading to PRL hypersecretion and breast stimulation. Herein, we describe the effect of bromocriptine and consequently the reduction in serum PRL levels on the ultrastructure of rat mammary glands.Female Long-Evans rats, 23 months of age, were divided into control and bromocriptine-treated groups. The control animals were injected subcutaneously once daily with a 10% ethanol vehicle and were later divided into a normoprolactinemic control group with serum PRL levels under 30 ng/ml and a hyperprolactinemic control group with serum PRL levels above 30 ng/ml.


2007 ◽  
Author(s):  
Mary B. Shea ◽  
Ginger A. Wooden ◽  
Karrine Henningsen ◽  
Robyn L. Jarvis

2013 ◽  
Vol 109 (10) ◽  
pp. 2505-2516 ◽  
Author(s):  
Fu-Zen Shaw ◽  
Yi-Fang Liao ◽  
Ruei-Feng Chen ◽  
Yu-Hsing Huang ◽  
Rick C. S. Lin

The contribution of the zona incerta (ZI) of the thalamus on spike-wave discharges (SWDs) was investigated. Chronic recordings of bilateral cortices, bilateral vibrissa muscle, and unilateral ZI were performed in Long-Evans rats to examine the functional role of SWDs. Rhythmic ZI activity appeared at the beginning of SWD and was accompanied by higher-oscillation frequencies and larger spike magnitudes. Bilateral lidocaine injections into the mystacial pads led to a decreased oscillation frequency of SWDs, but the phenomenon of ZI-related spike magnitude enhancement was preserved. Moreover, 800-Hz ZI microstimulation terminates most of the SWDs and whisker twitching (WT; >80%). In contrast, 200-Hz ZI microstimulation selectively stops WTs but not SWDs. Stimulation of the thalamic ventroposteriomedial nucleus showed no obvious effect on terminating SWDs. A unilateral ZI lesion resulted in a significant reduction of 7- to 12-Hz power of both the ipsilateral cortical and contralateral vibrissae muscle activities during SWDs. Intraincertal microinfusion of muscimol showed a significant inhibition on SWDs. Our present data suggest that the ZI actively modulates the SWD magnitude and WT behavior.


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