Determination of functionally essential neuronal population of the olfactory epithelium for nipple search and subsequent suckling behavior in newborn rats.
Neuronal population of the olfactory epithelium required for nipple search and subsequent suckling behavior was examined in newborn rats. After unilateral ablation of the olfactory bulb, different concentrations of ZnSO(4) were contralaterally injected into the nasal cavity to produce varying degrees of neuronal degeneration in the olfactory epithelium. The ZnSO(4)-treatment resulted in two populations of pups. One exhibited suckling while the other did not, and intact olfactory receptor neurons were quantified immunohistochemically using an antibody for olfactory marker protein (OMP), a marker protein for olfactory receptor neurons. The total numbers of the OMP (+) cells in the ZnSO(4)-treated pups with suckling capability ranged between 2457 and 4615, whereas those in the ZnSO(4)-treated pups without suckling capability ranged between 112 and 2398. With the mean value (4969) of the total numbers of the OMP (+) cells of the normal/control pups assumed to represent 100%, the total numbers of the OMP (+) cells accounted for 49-93% in the suckling (+) group and 2-48% in the suckling (-) group. From these findings, we conclude that approximately 50% of neuronal population of the olfactory epithelium is a critical value to distinguish between the two groups with and without suckling capability in the unilateral olfactory system of newborn rats.
Kawagishi
Kyutaro
K
Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan. kyutaro@shinshu-u.ac.jp
Yokouchi
Kumiko
K
Fukushima
Nanae
N
Sakamoto
Michio
M
Sumitomo
Norimi
N
Moriizumi
Tetsuji
T
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001070:Appetitive Behavior / Q000502:physiology*; D002452:Cell Count; D005247:Feeding Behavior / Q000502:physiology*; D007150:Immunohistochemistry; D007774:Lactation / Q000502:physiology*; D009410:Nerve Degeneration / Q000139:chemically induced; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009498:Neurotoxins / Q000633:toxicity; D009830:Olfactory Bulb / Q000293:injuries; D051842:Olfactory Marker Protein / Q000378:metabolism; D009831:Olfactory Mucosa / Q000187:drug effects / Q000294:innervation* / Q000502:physiology*; D018034:Olfactory Receptor Neurons / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D019287:Zinc Sulfate / Q000633:toxicity
D009498:Neurotoxins; D051842:Olfactory Marker Protein; C497599:Omp protein, rat; D019287:Zinc Sulfate