It has long been known that the intracerebroventricular administration of ACTH1-24 increases the duration of grooming episodes and the frequency of yawning in rats. The objective of this study was to investigate in what way these episodes are prolonged and whether and to what extent genotype influences such effects. We compared the effect of increasing doses of intracerebroventricular injection...

Eleven derivatives of 7,12-dimethylbenz(a)anthracene were tested for carcinogenicity in Sprague-Dawley female rats by the s.c. injection of 1.0 or 0.1 mg of compound dissolved in 0.1 ml of sesame oil on alternate days for 20 doses. Eight derivatives [7-hydroxymethyl-12-methyl-, 7-formyl-l 2-methyl-, 7-methoxymethyl-l 2-methyl-, 7-acetoxymethyl-l 2-methyl-, 7-benzoyloxymethyl-l 2-methyl-. 7-iodo...

Results of a study on Wistar rats regarding a possible carcinogenic effect of vinylidene chloride (VDC) were presented previously by one of the authors. Due to the unclear character of these results, a second inhalation study was initiated with Sprague-Dawley rats. Groups of 60 animals were exposed to 100 and 75 ppm VDC, along with one control group. A final report on the pathological results m...

A single exposure to severe stressors has been shown to cause anorexia in the next 24 h, but the duration of such alterations is not known. Male Sprague-Dawley rats were subjected to different stressors, and food intake was measured for several days after stress. In experiment 1, 2 h of immobilization (Imo) and lipopolysaccharide (LPS) administration (1,000 microgram/kg) caused a marked anorexi...

The effect of high salt intake on rascular and renomedullary prostaglandin (PG) synthesis was compared in Sprague-Dawley and salt-sensitive (S) and -resistant (R) Dahl rats. Animals were given a diet containing either 0.6% or 8% NaCI starting at 5 weeks of age, and were sacrificed 6 weeks later. Systolic blood pressure of S rats increased to 220 ± 7 mm Hg but was unaffected in R and Sprague-Daw...

The effect of high salt intake on vascular and renomedullary prostaglandin (PG) synthesis was compared in Sprague-Dawley and salt-sensitive (S) and -resistant (R) Dahl rats. Animals were given a diet containing either 0.6% or 8% NaCl starting at 5 weeks of age, and were sacrificed 6 weeks later. Systolic blood pressure of S rats increased to 220 +/- 7 mm Hg but was unaffected in R and Sprague-D...

Exposure of a male or nonpregnant female rat to a novel environment, such as a simulated open field, induces a transient increase in core temperature, which is often called stress-induced hyperthermia. Pregnancy alters this response such that the core temperature index increases significantly during exposure to a simulated open field on day 10 but not on days 15 and 20 of gestation in rats. The...

The touchscreen testing method for rodents is a computer-automated behavioral testing method that allows computer graphic stimuli to be presented to rodents and the rodents to respond to the computer screen via a nose-poke directly to the stimulus. The advantages of this method are numerous; however, a systematic study of the parameters that affect learning has not yet been conducted. We theref...

The preference of female Sprague-Dawley rats for sucralose, a non-nutritive sweetener derived from sucrose, was evaluated in 23 h two-bottle tests with water or saccharin. Overall, the rats displayed weak or no preferences for sucralose (0.25-4 g/l) over water but strong preferences for saccharin (0.5-8 g/l) over water and saccharin (1 g/l) over sucralose (0.5 g/l). The rats also preferred a sa...

It is well established that patterns of sensory input can affect neuroplastic changes during early development. The scope and consequences of experience-dependent plasticity in the adult are less well understood. We studied the possibility that repeated exposure to trains of stroboscopic stimuli could induce a sensitized and potentially aberrant response in ordinary individuals. Chronic electro...