title: Effect of suckling on NADPH-diaphorase (Nitric oxide synthase, NOS) reactivity and NOS gene expression in the paraventricular and supraoptic nuclei of lactating rats.
abstract: This study examined the effect of suckling on nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d, a histochemical marker for nitric oxide synthase, NOS) reactivity and neuronal NOS mRNA expression in the paraventricular (PVN) and supraoptic (SON) nuclei of lactating rats. Freely nursing (non-separated) dams and those separated from pups for 12 h and then reunited for 0, 15, 30, 60, 90, 120 and 180 min were used for the study. Dams separated from pups and sacrificed at time zero (without reunion) showed a significant decrease in NADPH-d staining and NADPH-d positive cells as well as in the NOS mRNA expression in the PVN and SON compared to that observed in non-separated dams. Reunion with pups and restoration of suckling significantly increased NADPH-d reactivity after 15, 30, 60 min, but not after 90, 120 and 180 min compared to non-reunited pups-deprived dams. A pattern of NADPH-d reactivity and neuronal NOS mRNA expression indistinguishable from that observed during free lactation was reinstated shortly (15 min) after the restoration of suckling stimulus, suggesting that the NADPH-d reactivity in lactation depends on the presence of the suckling stimulus. These results show that suckling stimulus may play a modulatory role in the regulation of NOS reactivity in the magnocellular neurones of the hypothalamic PVN and SON during lactation.
authors.affiliation: Department of Physiology, Kochi Medical School, Nankoku, Kochi, Japan. otukonyo@kochi-ms.ac.jp
authors.forename: E E
authors.initials: EE
authors.lastname: Otukonyong
authors.forename: C O
authors.initials: CO
authors.lastname: Okere
authors.forename: L E
authors.initials: LE
authors.lastname: Johnstone
authors.forename: T
authors.initials: T
authors.lastname: Murata
authors.forename: H
authors.initials: H
authors.lastname: Kaba
authors.forename: T
authors.initials: T
authors.lastname: Higuchi
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000033:anatomy & histology; D005260:Female; D015870:Gene Expression / Q000502:physiology*; D006651:Histocytochemistry / Q000379:methods; D007026:Hypothalamic Area, Lateral / Q000201:enzymology; D017403:In Situ Hybridization; D007774:Lactation / Q000502:physiology*; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000235:genetics*; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013194:Staining and Labeling; D013495:Supraoptic Nucleus / Q000502:physiology*; D015430:Weight Gain
chemical_list: D012333:RNA, Messenger; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase