TY - JOUR
T1 - Regeneration of 5-HT fibers in hippocampal heterotopia of methylazoxymethanol-induced micrencephalic rats after neonatal 5,7-DHT injection
AU - Nakamura, Arata
AU - Kadowaki, Taro
AU - Sakakibara, Shin Ichi
AU - Yoshimoto, Kanji
AU - Hirata, Koichi
AU - Ueda, Shuichi
N1 - Funding Information:
Acknowledgments This work was supported by a grant from the Academic Frontier Project of The Ministry of Education, Culture, Sports, Science and Technology, Japan (to S.U.).
PY - 2010/3
Y1 - 2010/3
N2 - In order to elucidate the regeneration properties of serotonergic fibers in the hippocampus of methylazoxymethanol acetate (MAM)-induced micrencephalic rats (MAM rats), we examined serotonergic regeneration in the hippocampus following neonatal intracisternal 5,7-dihydroxytryptamine (5,7-DHT) injection. Prenatal exposure to MAM resulted in the formation of hippocampal heterotopia in the dorsal hippocampus. Immunohistochemical and neurochemical analyses revealed hyperinnervation of serotonergic fibers in the hippocampus of MAM rats. After neonatal 5,7-DHT injection, most serotonergic fibers in the hippocampus of 2-week-old MAM rats had degenerated, while a small number of serotonergic fibers in the stratum lacunosum-moleculare (SLM) of the hippocampus and in the hilus adjacent to the granular cell layer of the dentate gyrus (DG) had not. Regenerating serotonergic fibers from the SLM first extended terminals into the hippocampal heterotopia, then fibers from the hilus reinnervated the DG and some fibers extended to the heterotopia. These findings suggest that the hippocampal heterotopia exerts trophic target effects for regenerating serotonergic fibers in the developmental period in micrencephalic rats.
AB - In order to elucidate the regeneration properties of serotonergic fibers in the hippocampus of methylazoxymethanol acetate (MAM)-induced micrencephalic rats (MAM rats), we examined serotonergic regeneration in the hippocampus following neonatal intracisternal 5,7-dihydroxytryptamine (5,7-DHT) injection. Prenatal exposure to MAM resulted in the formation of hippocampal heterotopia in the dorsal hippocampus. Immunohistochemical and neurochemical analyses revealed hyperinnervation of serotonergic fibers in the hippocampus of MAM rats. After neonatal 5,7-DHT injection, most serotonergic fibers in the hippocampus of 2-week-old MAM rats had degenerated, while a small number of serotonergic fibers in the stratum lacunosum-moleculare (SLM) of the hippocampus and in the hilus adjacent to the granular cell layer of the dentate gyrus (DG) had not. Regenerating serotonergic fibers from the SLM first extended terminals into the hippocampal heterotopia, then fibers from the hilus reinnervated the DG and some fibers extended to the heterotopia. These findings suggest that the hippocampal heterotopia exerts trophic target effects for regenerating serotonergic fibers in the developmental period in micrencephalic rats.
KW - Hippocampal heterotopia
KW - Methylazoxymethanol acetate
KW - Micrencephalic rat
KW - Regeneration
KW - Serotonergic fibers
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U2 - 10.1007/s12565-009-0052-z
DO - 10.1007/s12565-009-0052-z
M3 - Article
C2 - 19582544
AN - SCOPUS:77249159314
SN - 1447-6959
VL - 85
SP - 38
EP - 45
JO - Anatomical Science International
JF - Anatomical Science International
IS - 1
ER -