The plateau zokors' learning and memory ability is related to the high expression levels of foxP2 in the brain / 生理学报

Plateau zokor (Myospalax baileyi) is a subterranean mammal. Plateau zokor has high learning and memory ability, and can determine the location of blocking obstacles in their tunnels. Forkhead box p2 (FOXP2) is a transcription factor implicated in the neural control of orofacial coordination and sensory-motor integration, particularly with respect to learning, memory and vocalization. To explore the association of foxP2 with the high learning and memory ability of plateau zokor, the cDNA of foxP2 of plateau zokor was sequenced; by using plateau pika as control, the expression levels of foxP2 mRNA and FOXP2 protein in brain of plateau zokor were determined by real-time PCR and Western blot, respectively; and the location of FOXP2 protein in the brain of plateau zokor was determined by immunohistochemistry. The result showed that the cDNA sequence of plateau zokor foxP2 was similar to that of other mammals and the amino acid sequences showed a relatively high degree of conservation, with the exception of two particular amino acid substitutions [a Gln (Q)-to-His (H) change at position 231 and a Ser (S)-to-Ile (I) change at position 235]. Higher expression levels of foxP2 mRNA (3-fold higher) and FOXP2 protein (>2-fold higher) were detected in plateau zokor brain relative to plateau pika brain. In plateau zokor brain, FOXP2 protein was highly expressed in the cerebral cortex, thalamus and the striatum (a basal ganglia brain region). The results suggest that the high learning and memory ability of plateau zokor is related to the high expression levels of foxP2 in the brain.

Differences of glycolysis in skeletal muscle and lactate metabolism in liver between plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae) / 生理学报

The plateau pika (Ochotona curzoniae) and plateau zokor (Myospalax baileyi) are specialized native species of the Qinghai-Tibetan plateau. The goal of this study was to examine physiological differences in skeletal muscle glycolysis and hepatic lactate metabolism between these two species. The partial sequence of pyruvate carboxylase (PC) gene was cloned and sequenced. The mRNA expression levels of PC and lactate dehydrogenases (LDH-A, LDH-B) were determined by real-time PCR. The enzymatic activity of PC was measured using malic acid coupling method. The concentration of lactic acid (LD) and the specific activities of LDH in liver and skeletal muscle of two species were measured. The different isoenzymes of LDH were determined by native polyacrylamide gel electrophoresis (PAGE). The results showed that, (1) LDH-B mRNA level in skeletal muscle of plateau zokor was significantly higher than that of plateau pika (P < 0.01), but no differences was found at LDH-A mRNA levels between them (P > 0.05); (2) PC, LDH-A and LDH-B mRNA levels in liver of plateau pika were significantly higher than those of plateau zokor (P < 0.01); (3) The LDH activity and concentration of LD in skeletal muscle and liver, as well as the PC activity in liver of plateau pika were significantly higher than those of plateau zokor (P < 0.01); (4) The isoenzymatic spectrum of lactate dehydrogenase showed that the main LDH isoenzymes were LDH-A4, LDH-A3B and LDH-A2B2 in skeletal muscle of plateau pika, while the main LDH isoenzymes were LDH-AB3 and LDH-B4 in skeletal muscle of plateau zokor; the main isoenzymes were LDH-A3B, LDH-A2B2, LDH-AB3 and LDH-B4 in liver of plateau pika, while LDH-A4 was the only isoenzyme in liver of plateau zokor. These results indicate that the plateau pika gets most of its energy for sprint running through enhancing anaerobic glycolysis, producing more lactate in their skeletal muscle, and converting lactate into glucose and glycogen in the liver by enhancing gluconeogenesis. As a result, the plateau pika has a reduced dependence on oxygen in its hypoxic environment. In contrast, plateau zokor derives most of its energy used for digging activity by enhancing aerobic oxidation in their skeletal muscle, although they inhabit hypoxic underground burrows.