Tree shrew

Scandentia (1/1) Tree Shrews are relatively well studied for peripheral and central AOS components (Clark, 1924 Loo, 1972 Skeen, 1977 Frahm, 1984). Chemosignals are little known (Stralendorf, 1986). 

Fig. 2.2 External nose, (a) Rhinoglyphics lateral view of rhinarial surface, epidermal sculpturing and crenellations in Tree Shrew (Tupaia spp.), naked area encloses nostril (from Klauer, 1984). (b) Upper lip and rhinarium variants among carnivores (ventral view, Mongooses). 1. Narrow Philtrum and medial sulcus, 2. medial sulcus, Philtrum absent (from Pocock, 1914).

Frahm H.D., Stephan H. and Baron G. (1984). Comparison of accessory olfactory bulb volumes in the Common Tree Shrew (Tupaia glis). Acta Anat 119, 129-135. 

Skeen L.C. and Hall W. (1977). Efferent projection of the main and the accessory olfactory bulb in tree Shrew (Tupaia glis). J Comp Neurol 172, 1-36. 

Stralendorf F. von. (1986). Urinary chemosignals and specific behavioural responses in Tree Shrews. J Chem Ecol 12, 99-106. 

The chinning response in tree shrews, Tupaia lelangeri, is triggered by several lipophilic fractions of male urine. The combined fractions are more active than single fractions. Pyrazine compounds and a high concentration of several volatile monocarboxylic acids characterize male urine. Some pyrazine compounds and some monocarboxylic acids release the chinning response (StralendorfF, 1987). 

The mixtures of volatiles in the urine of tree shrews, T. belangeri, are sex specific but no single sex-spedfic compounds have been found (Stralendorff, 1987). 

Kawamichi, T. and Kawamichi, M. (1979). Spatial organization and territory of tree shrews (Tupaia glis). Animal Behaviour 17,381-393. 

Stralendorff, F. V. (1987). Partial chemical characterization of urinary signaling pheromone in tree shrews Tupaia belangeri). Journal of Chemical Ecology 13, 655-679. 

Gould E, McEwen BS, Tanapat P, et al (1997) Neurogenesis in the dentate gyrus of the adult tree shrew is regulated by psychosocial stress and NMDA receptor activation. J Neurosci 17 2492-2498... 

Margarinos A, McEwen BS, Flugge G, Fuchs E (1996) Chronic psychosocial stress causes apical dendritic atrophy of hippocampal CA3 pyramidal neurons in subordinate tree shrews. J Neimosci 16 3534-3540... 

Ming-Peng et al. (1990) studied high density lipoproteins and prevention of experimental atherosclerosis in tree shrews (Tupaia belangera yunalis). In contrast to rabbits, no increased lipid deposition in aortic intima after cholesterol feeding was found in tree shrews. 

Ming-Peng S, Ren-Yi X, Bi-Fang R, Zong-Li W (1990) High density lipoproteins and prevention of experimental atherosclerosis with special reference to tree shrews. Ann New Acad Sci 598 339-351... 

Sweet potato Thermal expansion Tree shrews... 

Chronic subordinate stress can be modeled using male tree shrews. This confrontational paradigm pits two male shrews against each other to establish a dominant-subordinate hierarchy as a result, the subordinate endures a stress-dependent chronic overdrive in sympathetic activation (56). Although the mechanisms are not clear, chronic subordinate stress correlates with decreased levels of a2A-AR messenger ribonucleic acid (mRNA) expression (57). 

It is interesting to note the parallels observed when assessing the behavioral despair seen in a2A-AR / mice with the findings in the male tree shrew subordinate stress model these collective data suggest that chronic stress may (via an unknown mechanism) reduce beneficial effects of the a2A-AR in depression and stress, leading to behavioral despair, as witnessed in animals deficient for the oc2A-AR. Moreover, a2A-AR activation (or protection from downregulation) could offer a protective mechanism to combat stressful or stress-related events. 

Fuchs E, Kramer M, Hermes B, Netter P, Hiemke C. Psychosocial stress in tree shrews clomipramine counteracts behavioral and endocrine changes. Pharmacol Biochem Behav 1996 54 219-228. 

Only few observations in primates are available on the corticonuclear projection of the posterior lobe. Haines and Whitworth (1978) and Haines and Patrick (1981) studied the projection of the paramedian lobule and the paraflocculus in the tree shrew Tupaia glis). They concluded that , 3 and a D zone, with a similar topography and corticonuclear projection as in the cat, were present in the paramedian lobule of the tree shrew. The C2 and the D zone continued into the paraflocculus, where the D zone could be subdivided into D, and Dj zones on the basis of its differential projection to the lateral cerebellar nucleus. The organization of the posterior vermis in primates (Haines, 1975a,b) will be dealt with in the Sections on the vestibular cerebellum (6.1.5.) and the olivocerebellar projection (6.3.3.3.). 

Haines DE (1975a) Cerebellar cortical efferents of the posterior lobe vermis in a prosimian primate (Galago) and the tree shrew (Tupaia). J. Comp. Neurol, 163, 21-40. 

Haines DE (1978a) Contralateral nucleocortical cells of the paraflocculus of tree shrew (Tupaia glis). Neurosci Lett., 8, 183-190. 

Haines DE (1978b) Cerebellar corticonuclear-nucleocortical topography A study of the tree shrew (Tupaia) paraflocculus. Anat. Rec., 190, 411. 

Haines DE, Patrick GW (1981) Cerebellar corticonuclear fibers of the paramedian lobule of tree shrew (Tupaia glis) with comments on zones. J. Comp. Neurol, 201, 99-119. 

Haines DE, Sowa TE, Dietrichs E (1985) Connections between the cerebellum and hypothalamus in the tree shrew (Tupaia glis). Brain Res., 328, 367 373. 

Mixtures of aflatoxins and aflatoxin B1 have been tested for carcinogenicity in several strains of mice and rats, in hamsters, fish, ducks, tree shrews and monkeys. Following oral administration, these compounds caused hepatocellular and/ or cholangiocellular liver tumours, including carcinomas, in all species tested except mice. However, intraperitoneal administration of aflatoxin B1 to infant mice did induce high incidences of liver tumours. Additionally, in some species, the compounds produced trunours at other sites in the body. For example, tumours in the kidney and colon were also found in rats. 

Recently, part of the mechanism for eye growth in myopia has been determined. Induction of myopia leads to decreased glycosaminoglycan synthesis, increased levels of matrix metalloproteinase-2, and decreased amounts of tissue inhibitor of matrix metalloproteinase-2 in the fibrous sclera of both chicks and tree shrews (65,66), while transforming growth factor (TGF)-p-2 regulates the visual eye growth in the final steps (67). 

McBrien NA, Lawlor P, Gentle A. Scleral remodeling during the development of and recovery from axial myopia in the tree shrew. Invest Ophthalmol Vis Sci 2000 41 3713-3719. 

Siegwart JT, Jr, Norton TT. Selective regulation of MMP and TIMP mRNA levels in tree shrew sclera during minus lens compensation and recovery. Invest Ophthalmol Vis Sci 2005 46 3484-3492. 

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