Sex and Regional Differences in the Time and Patterns of Neurogenesis of the Rat Substantia Nigra.
Abstract number :
2.012
Submission category :
Year :
2001
Submission ID :
918
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
A.S. Galanopoulou, MD PhD, Neurology, Albert Einstein College of Medicine, Bronx, NY; S. Liptakova, MD, Neurology, Albert Einstein College of Medicine, Bronx, NY; J. Veliskova, MD PhD, Neurology, Neuroscience, Albert Einstein College of Medicine, Bronx, N
RATIONALE: The substantia nigra reticulata (SNR) has been implicated in the control of seizures. Intranigral infusions of GABA(A)ergic agonists in developing rats revealed that the posterior SNR of male rats facilitates the development of flurothyl-induced seizures. In contrast, the anterior SNR undergoes a functional switch during the postnatal development from having a proconvulsant (male rats) or no effect (female rats) to mediating an anticonvulsant effect (both sexes). In this study, we investigated whether these sex and anteroposterior functional differences of SNR neurons could reflect differences in the time and pattern of neurogenesis in the substantia nigra (SN).
METHODS: Pregnant rats received a single intraperitoneal injection of BrdU (bromodeoxyuridine 100mg/kg) on the following gestational days: E13, E14 or E15. The offsprings (male and females) were perfused at postnatal day 30 (PN30). 40 [mu]m coronal adjacent sections containing the SN were immunostained using a combination of either (i) a mouse anti-parvalbumin (PRV) antibody (Ab) and a mouse anti-BrdU Ab or (ii) a rabbit anti-tyrosine hydroxylase (TH) Ab and the anti-BrdU Ab. We compared the numbers of dopaminergic (TH-positive), PRV-positive GABAergic neurons, and the subsets of proliferating (BrdU-positive) cells present in the anterior or posterior SN of each group.
RESULTS: The SN of female PN 30 rats was more cellular than the SN of males. Neurogenesis in SN was accomplished by E15. The SN of male rats, which received BrdU at E13 had more BrdU positive cells compared with same litter female rats, at all regions of the SN. The litters injected with BrdU at E14 manifested this tendency only in the posterior regions of the SN. The anterior SN showed an earlier peak of neuronal proliferation (E13 or earlier) compared with the posterior SN regions (E13 and E14).
CONCLUSIONS: These results suggest that: (1) The SN of female rats is more cellular that the SN of males. (2) Neurogenesis of the anterior SN (peak at E13 or earlier) occurs earlier than the posterior SN (peak at E13-E14). (3) The majority of SN neurons in males is born at E13-E14. (4) The peak of SN neurogenesis in female SN seems to be earlier than in males (E13 or earlier). The different timing and patterns of neurogenesis of the male and female SN may contribute to the different phenotypic and functional differences of SN neurons in postnatal life.
Support: EFA, NIH-NINDS NS20253 and NS30387