Histological reinterpretation of paraphysis cerebri in Ambystoma mexicanum
Por:
Rivas-Manzano, P., Torres-Ramirez, N., Parra-Gamez, L., Ortiz-Hernandez, R.
Publicada:
1 ago 2022
Resumen:
Intraventricular and extraventricular choroid plexuses are
neuroepithelial folds which arise from the roof of the diencephalon. We
describe the circumventricular structure of the diencephalon roof
(paraphysis cerebri) during the various development stages of Ambystoma
mexicanum. The parasagittal sections of the larvae epithalamus exhibit
the presence, in addition to the epiphysis, of two dorsal primordia in
nearby areas, which appear to be extraventricular saccular evaginations
of different origin that give rise to two structures we define as the
anterior extraventricular choroid plexus (AEP) and posterior
extraventricular choroid plexus (PEP). During larvae development, the
primordia arise perpendicular to each other, grow and show luminal folds
and invaginations. Later, the two extraventricular evaginations, which
are separate units, become interrelated. As the PEP grows, it covers the
AEP dorsally, but it is difficult to define the borders of these organs.
AEP is formed by alveolar-acinar epithelial aggregates with evidence of
secretion-like content. PEP structure is like a choroid plexus, but its
position is extraventricular and dorsal to the AEP. The PEP is always
between the AEP and the meninges and can be small or large in size. This
means that in A. mexicanum, the paraphysis cerebri is made up of two
adjacent organs, which arise almost simultaneously from two different
primordia (the AEP and the PEP) and as the posterior one grows, it
overlaps the anterior one and masks itself. In conclusion, we suggest
that AEP and PEP are homologous to paraphysis cerebri and the dorsal
sac, respectively.
Filiaciones:
Rivas-Manzano, P.:
Univ Nacl Autonoma Mexico, Fac Ciencias, Dept Biol Comparada, Ave Univ 3000,Cd Univ, Ciudad De Mexico 04510, Mexico
Torres-Ramirez, N.:
Univ Nacl Autonoma Mexico, Fac Ciencias, Dept Biol Celular, Ave Univ 3000,Cd Univ, Ciudad De Mexico 04510, Mexico
Parra-Gamez, L.:
Univ Nacl Autonoma Mexico, Fac Med, Dept Anat, Ave Univ 3000,Cd Univ, Ciudad De Mexico 04510, Mexico
Ortiz-Hernandez, R.:
(Corresponding Author), Univ Nacl Autonoma Mexico, Fac Ciencias, Dept Biol Celular, Ave Univ 3000,Cd Univ, Ciudad De Mexico 04510, Mexico
Univ Nacl Autonoma Mexico, Fac Ciencias, Dept Biol Celular, Ave Univ 3000,Cd Univ, Ciudad De Mexico 04510, Mexico
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