African mole-rats (family Bathyergidae) are small to medium sized, long-lived, and strictly subterranean
rodents that became valuable animal models as a result of their longevity and diversity in social
organization. The formation and integration of new hippocampal neurons in adult mammals (adult
hippocampal neurogenesis, AHN) correlates negatively with age and positively with habitat complexity. Here
we present quantitative data on AHN in wild-derived mole-rats of 1 year and older, and briefly describe its
anatomical context including markers of neuronal function (calbindin and parvalbumin). Solitary Cape molerats
(Georychus capensis), social highveld mole-rats (Cryptomys hottentotus pretoriae), and eusocial naked
mole-rats (Heterocephalus glaber) were assessed. Compared to other rodents, the hippocampal formation
in mole-rats is small, but shows a distinct cytoarchitecture in the dentate gyrus and CA1. Distributions of
the calcium-binding proteins differ from those seen in rodents; e.g., calbindin in CA3 of naked mole-rats
distributes similar to the pattern seen in early primate development, and calbindin staining extends into the
stratum lacunosum-moleculare of Cape mole-rats. Proliferating cells and young neurons are found in low
numbers in the hippocampus of all three mole-rat species. Resident granule cell numbers are low as well.
Proliferating cells expressed as a percentage of resident granule cells are in the range of other rodents,
while the percentage of young neurons is lower than that observed in surface dwelling rodents. Between
mole-rat species, we observed no difference in the percentage of proliferating cells. The percentages of
young neurons are high in social highveld and naked mole-rats, and low in solitary Cape mole-rats. The
findings support that proliferation is regulated independently of average life expectancy and habitat.
Instead, neuronal differentiation reflects species-specific demands, which appear lower in subterranean
De Vries, J.L.; Sichilima, Alfred Matafwali; Bennett, Nigel C., 1961-; Oosthuizen, Maria Kathleen(Blackwell, 2008)
Circadian rhythms of locomotor activity have been investigated in several African mole-rat species. Even though mole-rats spend most of their lives in underground burrows devoid of light, studies have shown that they do ...
Oosthuizen, Maria Kathleen(University of Pretoria, 2008-08-11)
The seasonality of wild caught Cape mole-rats was investigated, focusing on endocrine, neuroendocrine and neuroanatomical parameters. The Cape mole-rat reproduces only during the winter rainfall period of the western Cape ...
Bennett, Nigel C., 1961-; Coen, Clive W.; Kalamatianos, Theodosis; Oosthuizen, Maria Kathleen; Poorun, Ravi; Faulkes, Christopher G., 1959-(Wiley, 2015-11)
Various aspects of social behavior are influenced by the
highly conserved corticotrophin-releasing factor (CRF)
family of peptides and receptors in the mammalian telencephalon.
This study has mapped and compared the ...