Potential of PSA-NCAM in neuron-glial plasticity in the adult hypothalamus: role of noradrenergic and GABAergic neurotransmitters.
The present study was designed to establish the dynamic regulation of polysialylated form of neural cell adhesion molecule (PSA-NCAM) expression by neurotransmitters controlling gonadotropin releasing hormone (GnRH) secretion. The expression of PSA-NCAM and glial fibrillary acidic protein (GFAP) on GnRH cell bodies and axon terminals in the medial preoptic area (mPOA) and median eminence-arcuate (ME-ARC) region of hypothalamus was studied in the proestrous phase of cycling rats treated with alpha-adrenergic receptor blocker phenoxybenzamine (PBZ) and gamma-aminobutyric acid (GABA) by using dual immunohistofluorescent staining and Western blot hybridization. To further elucidate whether activity mediated regulation of PSA-NCAM in GnRH neuron is via regulation of PSA biosynthesis by polysialytransferase (PST) enzyme, the expression of PST-1 enzyme was studied by using fluorescent in situ hybridization (FISH). Both GnRH and PSA-NCAM immunostaining was much higher in the mPOA and ME-ARC region from proestrous phase rats, whereas, PBZ and GABA treatments significantly reduced their expression, GFAP-ir and its content were increased in the PBZ and GABA treated proestrous rats. Taken together, our observations add to the growing evidence that PSA-NCAM plays permissive role for neuronal-glial remodeling and further suggest a functional link between activity dependent structural remodeling in GnRH neurons. Further, enhanced mRNA expression of PST suggests that the biosynthesis of PSA on NCAM is regulated at the transcriptional level.
Parkash
Jyoti
J
Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India.
Kaur
Gurcharan
G
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D007031:Hypothalamus / Q000166:cytology*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism*; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism*; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000502:physiology*; D010643:Phenoxybenzamine / Q000494:pharmacology; D011359:Proestrus / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012794:Sialic Acids / Q000378:metabolism*; D012799:Sialyltransferases / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D005904:Glial Fibrillary Acidic Protein; D039842:Neural Cell Adhesion Molecule L1; D012794:Sialic Acids; C103469:polysialyl neural cell adhesion molecule; D010643:Phenoxybenzamine; D007987:Gonadotropin-Releasing Hormone; D005680:gamma-Aminobutyric Acid; C046778:CMP-N-acetylneuraminate-poly-alpha-2,8-sialosyl sialyltransferase; D012799:Sialyltransferases; D009638:Norepinephrine