The Structure of the Brachial Plexus of the Djungarian Hamster (Phodopus sungorus)

Hamsters are often chosen as companion animals but are also a group of animals frequently subjected to laboratory tests. As there are no scientific publications providing information on the anatomical architecture of the brachial plexus of the Djungarian hamster, this study analyses the structure of this part of the nervous system of this species. It is important to know the details of this structure not only for cognitive reasons, but also due to the increasing clinical significance of rodents, which are often used in scientific research. The study was conducted on 55 specimens. Like in humans, the brachial plexus of the Djungarian hamster has three trunks. The following individual nerves innervating the thoracic limb of the Djungarian hamster: the radial nerve, median nerve, ulnar nerve, musculocutaneous nerve, axillary nerve, suprascapular nerve, thoracodorsal nerve, cranial pectoral nerves, caudal pectoral nerve, lateral thoracic nerve, long thoracic nerve, and subscapular nerves. Similarly to other mammals of this order, the brachial plexus of the Djungarian hamster ranges widely (C5-T1). However, its nerves are formed from different ventral branches of the spinal nerves than in other mammals.

Partial uterine prolapse and ovarian cysts in two Djungarian hamsters

A 2-year-old multiparous (Case 1) and a 2.5-year-old nulliparous (Case 2) Djungarian hamster each presented with a history of a prolapsed mass from the vulva. A partial uterine prolapse was diagnosed in both cases, according to the clinical and diagnostic examinations. The prolapsed mass was replaced in each hamster, and an ovariohysterectomy was performed. The histopathological examination of the removed tissues revealed a cyst and papillary hyperplasia in the ovary. This first case report, to our knowledge, demonstrates the possibility of a uterine prolapse with a cyst and papillary hyperplasia in the ovary and how to surgically manage this condition. The report could also contribute to having a better understanding of the occurrence of a uterine prolapse without parturition in hamsters.

What can seasonal models teach us about energy balance?

Torpid states are used by many endotherms to save energy during winter. During torpor, metabolic rate is downregulated to fractions of resting metabolic rate and often associated with a severe drop in body temperature that challenges mammalian physiology. Understanding the mechanisms regulating this extreme depression of metabolism bears enormous potential for biomedical research. Torpor behavior has been extensively studied in the Djungarian hamster, also known as Siberian hamster. It is dependent on many preparatory adaptations of physiological and endocrine systems that are likely to be integrated by the hypothalamus eventually controlling metabolism. Although substantial knowledge exists about prerequisites and characteristics of torpor in this species, the cascade of events and their mechanisms of action are not well understood. This review summarizes the current state of knowledge about mechanisms of metabolic regulation in the Djungarian hamster focusing on the potential roles of thyroid hormone and glucose metabolism.

Spaced and mass training within cognitive experimental paradigm in the Djungarian hamster Phodopus sungorus: comparative psychological approach

Ability to shape associations between visual stimuli and a reward under conditions of mass and spaced trainings have been studied for the first time in wild Djungarian hamsters. In a case of a simple task (“spot vs no spot”) 7 from 9 animals solved the problem under condition of mass training, whereas under condition of space training only one individual was successful. In a case of more complex task (“a lesser spot vs a greater one”) 4 from 9 animals were successful under condition of mass training. Taking into account our previous study of Ph.sungorus’s ability to evaluate sets of geometric figures, one can suggest that evaluation of visual stimuli in details is above cognitive competence of this species. Comparative psychological analysis of experimental studies enables us to consider this species a sort of “benchmark”, at least when discriminations of visual stimuli are concerned. In contrast to majority of rodent species as well as genetic lines, the Djungarian hamsters learn to discriminate visual stimuli under conditions of mass training only, that is, they have “short memories”.