To assess the changes in glycolysis of skeletal muscles within metabolic stress and to test whether metabolic stress-induced oxidative stress and malnutrition were associated with these changes, slow- (soleus) and fast-twitch extensor digitorum longus (EDL) muscles were studied in zymosan-induced critically ill, pair-fed and control rats for 7 days. Thiobarbituric acid reactive species (TBARS) concentrations were increased in both stressed and pair-fed rats. In slow-twitch muscle, the fructose-1,6-bisphosphate (F-1,6-P2)/fructose-6-phosphate (F-6-P) ratio was decreased in stressed rats and was not altered with increased food intake. F-1,6-P2/F-6-P ratio in soleus was correlated with both TBARS and muscle dry weight. In EDL, the F-1,6-P2/F-6-P was unaffected and neither oxidative stress nor muscle weight correlated with the ratio. In conclusion, metabolic stress-induced oxidative stress and malnutrition influenced glycolytic slowdown only in slow-twitch muscle.

This study examined the contributions of different brain areas to several of the behavior effects of amphetamine. The drug was micro-injected into each of six discreet brain sites in rats and the effects on behavior were examined. Amphetamine's rewarding effects were studied using the conditioned place preference (CPP) paradigm. Animals that had received injections into the nucleus accumbens showed a CPP, suggesting a rewarding effect of the drug. No effect was produced by injections into the medial frontal cortex, medial or lateral parts of the caudate nucleus, amygdala or the region around the area postrema. A conditioned taste aversion (CTA) towards a flavour that had been paired with the drug was produced by injections into the region around the area postrema, but not from the other sites. Anorexia and adipsia were both producted only by injections into the nucleus accumbens and amygdala. In the open field, increased activity was produced by intra-accumbens amphetamine injections, with smaller effects from the medial frontal cortex and medial caudate. Stereotyped behavior was not produced by any intra-cranial injection. The CPP, anorexia, adipsia and increase in activity that were produced by the intra-accumbens injections were interpreted as suggesting that the drug had stimulated approach behavior towards all stimuli, as if they had all become rewarding. The observation of a CPP from the accumbens and a CTA from the region around the area postrema suggests that the rewarding and apparently aversive effects of systemically injected amphetamine result from actions of the drug on different neuroanatomical substrates. Other hypotheses of the behavioral function of the neural substrates of the observed effects are presented.

This study examined the effects of early nutrition or, the body weight and adipose tissue characteristics of Sprague-Dawley rats. Different levels of caloric intake during the pre-weaning phase were achieved by manipulation of litter size. Immediately after birth, pups were redistributed into large (15-18 pups), control (1O pups), or small (4 pups) litters. Males from small litters demonstrated an increase in body weight and adipocyte, number (K.05), but this difference was not seen in the females. Litter size had no effect on adipc"cyte size or percent body fat. The effect of caloric restriction during the post-weaning phase was also examined. This was done by pair-feeding one-half of the rats raised in small litters to those raised in large litters for a period of 5 weeks. After ad libitum feeding was resumed, the pair-fed group demonstrated an increase "in adipocyte size which resulted in an increased level of fatness W.05). The results of this experiment demonstrate that the consequences of early nutrition are dependent on when it is undertaken, and suggest that sex hormones are involved in modulating these effects.

Augmented soft tissue mobilization therapy (ASTM) is a newly developed massage technique. ASTM is applied with the aid of specifically designed, solid instruments and has been successfully used in the treatment of chronic tendinitis patients. In a study on collage nase -injure d rat Achilles tendons treated with ASTM, Davidson et. al (1997) reported gait improvement as well as fibroblasts proliferation and suggested ASTM may augment healing by the recruitment of fibroblast. The present study examined the morphological response of enzyme-induced rat Achilles tendons to 3 different ASTM pressure application: 1 newton; 2 newtons and 3 newtons. Collagenase-injured tendons exhibited disrupted and randomly arranged collagen fibers. Treatment applications were performed for 4 days for a total of 4 treatments. Morphological differences were demonstrated between groups in proportion to the ASTM treatment pressure application. The ASTM group treated with 3 newtons demonstrated the greatest mean fibroblast count (370.3 +/- 51.6). Further, electron microscopy revealed the presence of activated fibroblasts in the tendons of the 3 newtons, ASTM group. However, immunochemical staining comparisons of Type I and III collagen, fibroblast growth factor receptor, and insulin-like growth factor between groups were not remarkable. / Department of Physiology and Health Science

Probiotics are live microorganisms that are similar to beneficial microorganisms found in the human gut. They are often known as lactic acid bacteria and are normally consumed in the form of yogurt. Most often the bacteria will come from two groups, Lactobacillus and Bifidobacterium. Vancomycin is a bactericidal antibiotic used in the treatment of antibiotic-associated colitis and endocarditis. In this study we will be examining the effects of vancomycin on the induced growth of lactobacilli in the Lewis male rat. The Lewis male rat was used because in the animal model of rheumatoid arthritis, vancomycin was shown to reduce the disease scores of adjuvant-induced arthritis and one research group also noted an increase in lactobacilli growth in the digestive tract with administration. As a control for this research project, to ensure induction of lactobacilli was achieved, Bene-Bac Pet powder was used. Bene-Bac Pet powder contains live, naturally occurring microorganisms and is recommended anytime an animal experiences changing nutritional or environmental conditions, one of them being antibiotic treatment. The rats were placed in four groups, two being control and the others being experimental. According to each group, rats were fed dextrose/maltodextrin substrate, Bene-Bac Pet powder, vancomycin and one group being fed both Bene-Bac powder and vancomycin. Fecal samples were obtained from the rat prior to initial treatment and then once every three days during the experimental period and two days after the conclusion of the experimental procedure (n=5 samples per rat). Samples were diluted and plated and the colony growth was noted. Vancomycin was expected to decrease the growth of lactobacilli in the Lewis rat following the treatments. There were significant changes (p = 0.02) among most groups by day 6 of the study. In contrast, there was an increase in the growth of lactobacilli in experimental groups. Vancomycin increases and maintains the growth of lactobacilli in the Lewis rat. / Department of Physiology and Health Science

Taste buds are spindle-shaped collections of taste receptor cells located in the surface epithelium of the oral cavity. Taste receptor cells are specialized sensory epithelial cells that are responsible for the transmission of taste information to the taste nerves. Immunocytochemical evidence of the neuropeptide cholecystokinin in various taste cells of the rat has been presented by our lab (Herness 1991). These results have prompted our investigation of the messenger RNA encoding this peptide in rat taste cells. CCK may play an important role in taste signal transmission or modulation.Three areas of the oral cavity were investigated for the presence of CCK mRNA. Two of these areas contain collections of taste buds in well-defined structures called papillae. Circumvallate papillae, located on the posterior surface of the tongue, and foliate papillae, located on the lateral surfaces of the tongue, were sectioned and probed for CCK mRNA using non-radiographic in situ hybridization. The third area investigated was the nasoincisor duct, located on the roof of the oral cavity. This duct contains isolated taste buds within the surface epithelium near the opening to the oral cavity.The results of this study confirm the presence of CCK mRNA in all three areas studied. Taste buds located in the circumvallate papillae, foliate papillae and in the nasoincisor duct all contain taste cells that express CCK mRNA. These results are verified by the absence of labeled cells in negative control experiments. The negative controls consists of the omission of probe, anti-DIG antibody, and the application of a sense probe. The immunocytochemical results show only a subset of taste cells labeled for the CCK peptide while the in situ results depict all cells in the bud labeled for CCK mRNA. The in situ results very closely parallel the immunocytochemical results previously obtained by our lab, although with in situ hybridization epithelial staining is more prominent. The surface epithelium contains the messenger RNA encoding CCK likely because taste receptor cells are derived from the lingual epithelium.Several roles for CCK can be considered in taste physiology. Taste reception and taste signal transduction is not fully understood. Also the localization and pharmacology of CCK receptors in taste systems awaits investigation. These two areas must be studied further to understand the function of CCK in taste cells. / Department of Biology

The role of the retinal pigment epithelial cells on the viability and renewal of photoreceptors has been well demonstrated in the Royal College of Surgeons (RCS) strain of rat. These rats are characterized by an inherited time-dependent degeneration of their photoreceptors. This degeneration is apparently due to the inability of the retinal pigment epithelial cells to adequately ingest fragments of photoreceptor membrane that are shed during the course of photoreceptor membrane renewal. The buildup of photoreceptor material in the interphotoreceptor space ultimately leads to the degeneration of photoreceptors in these animals. With regard to the pigment epithelial cells, neither the mechanism mediating the ingestion process in normal rats nor the nature of the defect of this process in RCS rats is understood.It is the goal of this proposed research to assay for the presence of phospholipase C in retinal pigment epithelial (RPE) cells and to determine possible modulators of the enzyme in an attempt to associate this with the process of phagocytosis. / Department of Biology

No description available.

We investigated the role of two intracellular second messengers, extracellular signal-regulated protein kinase (ERK), and protein kinase C (PKC) in a model of persistent pain, using intrathecal (i.t) (R,S )-DHPG to induce spontaneous nociceptive behaviours (SNBs). SNBs were measured in animals that were treated with an ERK inhibitor (PD 98059), and a PKC inhibitor (GF 109203X) compared with controls. Mechanical allodynia, was measured using paw withdrawal thresholds in the von Frey test, and thermal hyperalgesia was measured using response latencies in the plantar test. In study 1, it was shown that spinal administration of PD 98059, dose-dependently decreased SNBs, and reduced mechanical allodynia and thermal hyperalgesia. In study 2, it was shown that i.t. pretreatment with the GF 109203X, reduced SNBs and thermal hyperalgesia, but not mechanical allodynia. These results suggest that both ERK and PKC are involved in SNBs and the concomitant and thermal hyperalgesia and possibly mechanical allodynia.

Bibliography: leaves 216-239. / xiv, 246 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this thesis is to examine the relationship between vascular reactivity, contractile proteins and blood pressure development in the spontaneously hypertensive rat (SHR). In addition, the influence of angiotensin II on blood pressure and vascular structure and function is investigated. / Thesis (Ph.D.)--University of Adelaide, Dept. of Clinical and Experimental Pharmacology, 1997