Drinking behavior in the spiny mouse (Acomys cahirinus) following putative dipsogenic challenges

FYN: emerging biological roles and potential therapeutic targets in cancer

Src family protein kinases (SFKs) play a key role in cell adhesion, invasion, proliferation, survival, apoptosis, and angiogenesis during tumor development. In humans, SFKs consists of eight family members with similar structure and function. There is a high level of overexpression or hyperactivity of SFKs in tumor, and they play an important role in multiple signaling pathways involved in tumorigenesis. FYN is a member of the SFKs that regulate normal cellular processes. Additionally, FYN is highly expressed in many cancers and promotes cancer growth and metastasis through diverse biological functions such as cell growth, apoptosis, and motility migration, as well as the development of drug resistance in many tumors. Moreover, FYN is involved in the regulation of multiple cancer-related signaling pathways, including interactions with ERK, COX-2, STAT5, MET and AKT. FYN is therefore an attractive therapeutic target for various tumor types, and suppressing FYN can improve the prognosis and prolong the life of patients. The purpose of this review is to provide an overview of FYN's structure, expression, upstream regulators, downstream substrate molecules, and biological functions in tumors.

Which precocial rodent species is more suitable as the experimental model of microgravity influence on prenatal musculosketal development on international space station?

The International Space Station (ISS) has the possibility to perform experiments regarding rodent reproduction in microgravity. The musculoskeletal system at birth in precocial rodent species more resembles the human than that of altricial rodent species. For precocial rodent species with body weight ≤ 500 g (limit of ISS) determined were: adult body mass, newborn body mass, head-body length, tail length, existing variants (wild, domesticated, laboratory), single/group housing, dry food consumption/24 h, water intake/24 h, basal metabolic rate mlO2/g/h, environmental temperature, sand baths, urine output ml/24 h, fecal output g/24 h, size of fecal droplet, hair length, life span, length of oestrus cycle, duration of pregnancy, building nest, litter size, stage of musculoskeletal maturity at birth, and the duration of weaning. Characteristics were obtained by searching SCOPUS as well as the World Wide Web with key words for each of the species in English, Latin and, local language name. These characteristics were compared in order to find most appropriate species. Twelve precocial rodent species were identified. There is not enough data for Common yellow-toothed cavy, and Eastern spiny mouse. Inappropriate species were: Gundis, Dassie rat are a more demanding species for appropriate tending, litter size is small; Octodon degus requires sand baths as well as a nest during the first two weeks after delivery; muscle maturity of Spiny mouse at birth (myotubular stage), does not correspond to the human (late histochemical stage); Chinchilla requires separately housing, daily sand baths, has upper limit of weight. Possibility of keeping Southern mountain cavy as pet animal, short estrus, large litter size, absence of the need for nest and sand baths, makes this species the most promising candidates for experiments on ISS. If an experiment is planned with exposing gravid animals before term of the birth, then they might be kept together in the existing Rodent Habitat (USA). If an experiment with birth in microgravity is planned on ISS, the existing habitats do not provide conditions for such an experiment. It is necessary to develop habitats for separate keeping of pregnant animals to enable the following: 1. undisturbed delivery 2. prevent the possibility of hurting the newborns 3. ensure adequate post-partum maternal care and nursing.

A comparative study of renal function in the desert-adapted spiny mouse and the laboratory-adapted C57BL/6 mouse: response to dietary salt load

The desert-adapted spiny mouse has a significantly lower glomerular number, increased glomerular size, and a more densely packed renal papillae compared with the similar-sized laboratory-adapted C57BL/6 mouse. In the present study we examined the functional consequences of these structural differences in young adult male spiny and C57BL/6 mice and detailed the impact of 1 wk of a high-salt (10% wt/wt NaCl) diet. Basal food and water intake, urine and feces production, and urinary electrolyte concentrations were not different between species, although urinary urea concentrations were higher in spiny mice (P < 0.05). On normal salt, MAP of the anesthetized spiny mouse was approximately 18 mmHg lower, effective renal plasma flow (ERPF) was 40% lower (P < 0.001), and glomerular filtration rate (GFR) tended to be lower than in the C57BL/6 mouse. On the high-salt diet, both species had similar 24-h NaCl excretions; but C57BL/6 mice required a significantly increased amount of water (lower urine NaCl concentration) than the spiny mice. Filtration fraction was greater in both species on the high-salt diet. Spiny mice had greater GFR and ERPF after the high-salt diet, whereas the C57BL/6 mouse showed little change in GFR. The ability of the spiny mouse to tolerate a significantly higher plasma osmolality after salt, measured by a decreased drinking response, and the ability to increase ERPF at a lower MAP are features that allow this species to conserve water more efficiently than can be done in the C57BL/6 mouse. These features are important, particularly since the desert mouse has a smaller kidney, with fewer nephrons.

A comparison of chlordiazepoxide, bretazenil, L838,417 and zolpidem in a validated mouse Vogel conflict test

RATIONALE

GABAA receptors containing an alpha2 subunit are proposed to mediate the anxiolytic effect of benzodiazepines (BZ) based on studies in transgenic mice using unconditioned models of anxiety. Conditioned models of anxiety were not assessed and are rarely encountered in phenotyping of genetically modified animals. The novel benzodiazepine site ligand L838,417 is a partial agonist at GABAA receptors containing an alpha2, alpha3 or alpha5 subunit and an antagonist at alpha1 receptors, giving an anxiolytic profile devoid of sedation. However, this compound has not previously been assessed in mice.

OBJECTIVES

(1) Establish the Vogel conflict test (VCT) in C57BL/6J mice and validate it with a range of pharmacological tools and (2) compare the full and partial GABAA receptor positive modulators chlordiazepoxide (CDP) and bretazenil (BRZ), respectively, with the subtype selective ligands zolpidem (ZOL; alpha1 selective) and L838,417.

RESULTS

(1) enhanced thirst (water deprivation or isoproterenol administration), analgesia (lamotrigine) or cognitive impairment (MK-801) did not generate false positives in the VCT; (2) CDP and BRZ engendered linear dose-related anti-conflict effects and also increased unpunished drinking; (3) L838,417 engendered a bell-shaped anti-conflict effect and did not increase unpunished drinking; (4) the anti-conflict effect of CDP and L838,417 were antagonised by flumazenil, whereas BRZ's effect was insensitive to this antagonist; and (5) ZOL induced motoric deficits and no anti-conflict effect.

CONCLUSION

We have established the VCT in C57BL/6J mice and validated this test behaviourally, physiologically and pharmacologically. The novel GABAA receptor ligand L838,417 was anxiolytic in this mouse model, and unlike the non-selective compounds, had no effect on unpunished drinking.