The potential role of nitric oxide synthase in survival and regeneration of magnocellular neurons of hypothalamo-neurohypophyseal system.
Previous investigations from this laboratory have demonstrated that hypophysectomy induces up-regulation of neuronal nitric oxide synthase (nNOS) in magnocellular neurons of the mammalian hypothalamo-neurohypophyseal system (HNS). Accompanied by this upregulation of nNOS, both neuronal regeneration and degeneration are also observed in this system following hypophysectomy. The specific aim of this study was to determine the potential role of nNOS upregulation in neuronal survival and regeneration after hypophysectomy in the adult Sprague-Dawley (SD) rat by using a competitive nitric oxide synthase blocker, N(G)-nitrol-L: -arginine methyl ester (L: -NAME). We found that L: -NAME treatment effectively blocked the regeneration of magnocellular neurons of the rodent hypothalamus as observed in the lumen of the third cerebral ventricle following hypophysectomy. However, L: -NAME had no effect on the survival of magnocellular neurons in the supraoptic (SON) and paraventricular (PVN) nuclei after hypophysectomy. These results suggest that the induced increase of nNOS expression enhance the regenerative ability of magnocellular neurons of the HNS following hypophysectomy.
Yuan
Qiuju
Q
Department of Anatomy, The University of Hong Kong, Pokfulam, China. qiujuyuan@gmail.com
Scott
David E
DE
So
Kwow-Fai
KF
Lin
Zhixiu
Z
Wu
Wutian
W
D000818:Animals; D002470:Cell Survival; D007016:Hypophysectomy; D007030:Hypothalamo-Hypophyseal System / Q000166:cytology* / Q000187:drug effects; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009473:Neuronal Plasticity; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000502:physiology*; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration; D013495:Supraoptic Nucleus / Q000166:cytology / Q000187:drug effects
D052248:Nitric Oxide Synthase Type I; D019331:NG-Nitroarginine Methyl Ester