Premium
Vasoactive Intestinal Polypeptide‐containing Neurons and Processes in the Developing Hippocampus of Rats Prenatally Exposed to Methylazoxymethanol Acetate
Author(s) -
FUNAHASHI Atsushi
Publication year - 1995
Publication title -
congenital anomalies
Language(s) - English
Resource type - Journals
eISSN - 1741-4520
pISSN - 0914-3505
DOI - 10.1111/j.1741-4520.1995.tb00305.x
Subject(s) - vasoactive intestinal peptide , hippocampus , hippocampal formation , medicine , endocrinology , biology , chemistry , neuropeptide , receptor
Developmental alteration of the dendritic arborization and axonal boutons of vasoactive intestinal polypeptide (VIP) neurons in the CA1 hippocampus was immunohistochemically examined in both control and microcephalic rats at postnatal days 15 and 60. Microcephaly was induced by prenatal exposure to methylazoxymethanol acetate (MAM; 20 mg/kg) on day 15 of gestation (MAM rats). In the control at postnatal day 15, VIP‐immunoreactive axonal boutons were densely aggregated specifically in the stratum pyramidale. At postnatal day 60, these axonal boutons in the stratum pyramidale of the controls were somewhat less dense. Another aggregation of axonal boutons was also observed along the upper part of the stratum oriens near the alveus border (area A). In the MAM rats at postnatal day 15, on the other hand, VIP‐immunoreactive neurons in the CA1 hippocampus were decreased in number and the dendritic arborization of these neurons was very poor compared with the controls. The density of VIP‐immunoreactive axonal boutons was remarkably lower than the controls. In the MAM‐rats at postnatal day 60, density of the axonal boutons was almost similar with that of MAM‐rats at postnatal day 15 in the stratum pyramidale, whereas a drastic increase was observed in area A, which made the bouton aggregation more dense than in the controls at postnatal day 60. These observations suggest that there is an area‐dependent difference in the development of VIP neurons in the CA1 hippocampus which may be related to the area‐dependent heterogeneous vulnerability of VIP neurons to MAM exposure.