Postnatal maturation of brain cholinergic systems in the precocial murid <i>Acomys cahirinus</i>: Comparison with the altricial rat

Annita Pintor1, Enrico Alleva1,2, Hanna Michalek1
1Reparto di Farmacologia Biochimica, Laboratorio di Farmacologia, Laboratorio di Fisiopatologia di Organo e di Sistema, Istituto Superiore di Sanità, I-00161 Roma, Italy
2Reparto di Fisiopatologia Neurocomportamentale, Laboratorio di Fisiopatologia di Organo e di Sistema, Istituto Superiore di Sanità, I-00161 Roma, Italy

Tóm tắt

AbstractThe spiny mouse (Acomys cahirinus) is the only precocial murid species. It has some neuroanatomical peculiarities such as a relatively thin cerebral cortex and a large hippocampus. The levels of choline acetyltransferase. membrane‐bound acetylcholinesterase and muscarinic receptor sites (measured as [3H]quinuclidynil benzilate binding) were assessed in the whole brain on days 1, 7, 14, 21, 28 and 80 (adult), and compared with those of Wistar rats of the corresponding ages. At birth choline acetyltransferase was significantly higher in spiny mice than in rats but the adult levels were similar, with an overall increase of about 5.2‐ and 14‐fold for the former and the latter species, respectively. Membrane‐bound acetylcholinesterase level and maximal density of muscarinic receptor sites in spiny mice were considerably higher at birth, in contrast adult levels were significantly lower than in rats with a respective overall increase of about 1.5‐ and over 4.5‐fold. The high degree of maturity attained at birth by spiny mice partially depends on the long gestation period. However, if we consider postconception age, the maturation of choline acetyltransferase appears to be delayed at birth in the spiny mice, probably in relation to the lack of external stimulation during intrauterine life. In the cerebral cortex, hippocampus and striatum of adult spiny mice, when compared with the rats, there were similar levels of choline acetyltransferase but lower levels of membrane‐bound acetylcholinesterase and, in the cerebral cortex, lower density of muscarinic receptor sites.

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