Gender-specific 5-HT1A receptor changes in BrdU nuclear labeling patterns in neonatal dentate gyrus.
The actions of 5-HT1A receptors on cell proliferation in the rat neonatal dentate gyrus are unknown. We injected a 5-HT1A receptor agonist (ipsapirone) or antagonist (Way 100635) 1 h before injections of BrdU in neonates of both genders between days 2-4, a peak time of dentate gyrus granule cell proliferation. The BrdU immunoreactive (IR) nuclei in the granule cell layer and subgranular zone were examined after 2 weeks. The BrdU-IR nuclear staining patterns were classified as being either diffuse (homogenous dark BrdU-staining throughout the nucleus) or punctate (multiple distinct small stained spots within the nucleus). Most BrdU-labeled nuclei with a diffuse pattern were seen in the subgranular zone while the punctate pattern nuclei were seen within the granular cell layer of the dentate gyrus. 5-HT1A antagonist showed no overall change in absolute number or pattern of labeled nuclei compared to control animals. After a 5-HT1A agonist, there was also no differences in the total number of BrdU-IR nuclei (punctate and diffuse pattern). However, in both genders, the proportion of the BrdU-labeled nuclei showing a punctate compared to diffuse pattern increased: 33% in females and 18% in males. In females, the 5-HT1A receptor agonist increased the number of nuclei showing a punctate pattern by 41%, while in males the 5-HT1A receptor agonist decreased the number of nuclei showing a diffuse pattern by 29%. These results indicate gender-specific 5-HT1A receptor action on the state of nuclear DNA in the cells of the dentate gyrus, without increasing the total number of BrdU-labeled nuclei.
Greaves
John M
JM
Department of Biology, New York University, 10-09 Silver Building, 100 Washington Square East, New York, NY 10003, USA.
Russo
Sharon S
SS
Azmitia
Efrain C
EC
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001973:Bromodeoxyuridine / Q000378:metabolism / Q000494:pharmacology*; D002452:Cell Count / Q000379:methods; D018891:Dentate Gyrus / Q000254:growth & development* / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D010879:Piperazines / Q000494:pharmacology; D011247:Pregnancy; D011725:Pyridines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D012727:Sex Characteristics
D010879:Piperazines; D011725:Pyridines; D011743:Pyrimidines; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A; C043077:ipsapirone; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide; D001973:Bromodeoxyuridine