Computer Simulation of Inspiratory Airflow in All Regions of the F344 Rat Nasal Passages

Kimbell, Julia S.; Godo, Matthew N.; Gross, Elizabeth A.; Joyner, Donald R.; Richardson, Regina B.; Morgan, Kevin T.

doi:10.1006/taap.1997.8206

Cited by 183 publications

(141 citation statements)

References 31 publications

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“…One possible reason for this regional translation of eNOS mRNA is the airflow in the nasal passages. It is known that the airflow in the dorsomedial region of the rat nasal cavity is much faster than that in the other regions [25]. This region corresponds with the region containing intensely positive olfactory cells for eNOS.…”

Section: Discussionmentioning

confidence: 89%

Localization of eNOS in the Olfactory Epithelium of the Rat

Endo

Yamamoto

Yamaguchi-Yamada

et al. 2011

The Journal of Veterinary Medical Science

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ABSTRACT. Nitric oxide (NO) is a free radical and produced from L-arginine by nitric oxide synthase (NOS). Since NO is recently suggested to be involved in olfactory perception, the expression of eNOS, an isoform of NOS, was examined in the rat olfactory epithelium. The activity of NADPH-diaphorase was also examined as a marker of NOS. In the dorsomedial region of the nasal cavity, intensely positive reactions for NADPH-diaphorase were observed in the entire cytoplasm of sensory cells (olfactory cells). By immunohistochemistry, intensely positive reactions for eNOS were also found in the dorsomedial region of the nasal cavity. These reactions were observed on the free border of the olfactory epithelium. By immunoelectron microscopy, positive reactions for eNOS were found in the cilia of olfactory cells. In addition, in situ hybridization analysis of the olfactory epithelium revealed the expression of eNOS mRNA in the olfactory cells. These results indicate the presence of eNOS in the olfactory cells of the rat, and differential expression of eNOS in the olfactory epithelium depending on the regions of the nasal cavity. In addition, NO produced by eNOS may be involved in olfactory perception in the cilia of olfactory cells.KEY WORDS: eNOS, NADPH-diaphorase, nitric oxide, olfactory epithelium, rat.J. Vet. Med. Sci. 73(4): 423-430, 2011 Nitric oxide (NO) is a free radical with many functions in the cardiovascular, nervous, and immune systems [2]. Biologically, NO is produced from L-arginine by nitric oxide synthase (NOS). NOS is divided into 3 types of major isoforms, i.e., neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS). The nNOS and eNOS are constitutive forms of NOS and mainly expressed in the neuronal and endothelial cells, respectively. The iNOS is an inducible form of NOS and mainly expressed in macrophages [15].Primary function of NO is the activation of soluble guanylyl cyclase (sGC) to increase cGMP levels [1]. In the cilia of the rat sensory cells (olfactory cells), it is reported that odorant-stimulus induces the increase of cGMP levels and that specific NOS inhibitor L-N G -nitro arginine or NO scavenger hemoglobin inhibits this increase [4]. These findings indicate that odorant-stimulus induces NO production in the rat olfactory cells. Schmachtenberg et al. (2000Schmachtenberg et al. ( , 2003 reported that NO-stimulus induces outward potassium currents in 30 out of 72 olfactory cells and inward potassium currents in 3 out of 54 cells by physiological study [36,37]. In the cilia of rat olfactory cells, moreover, NO-stimulus is reported to activate or inhibit olfactory cyclic nucleotidegated (CNG) channels [5,6,28,36,37]. These reports suggest that NO is produced by the olfactory cells in response to odorant-stimulus, and has inhibitory and/or weakly excitatory effects to the olfactory cells by gating of CNG channel. However, it is still unclear which type of NOS isoforms generates NO in the olfactory cells of the rat. Because it has been reported that iNOS and eNOS are expressed...

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Section: Discussionmentioning

confidence: 89%

Localization of eNOS in the Olfactory Epithelium of the Rat

Endo

Yamamoto

Yamaguchi-Yamada

et al. 2011

The Journal of Veterinary Medical Science

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“…Four RNA samples (two male and two female) from independently pooled septal organs were used to obtain as many candidates as possible. Because we did not observe any significant gender differences, we treated Arrows indicate the medial air streams (Kimbell et al, 1997). SO, Septal organ; OB, olfactory bulb; NPH, nasopharynx.…”

Section: Resultsmentioning

confidence: 99%

Molecular Organization of the Olfactory Septal Organ

Tian¹,

Ma²

2004

J. Neurosci.

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The septal organ in the mammalian nose is a distinct chemosensory organ sitting in the air path. To gain insights into its organization and function, we analyzed the chemoreceptors expressed in this area. By combining cDNA cloning, Affymetrix (Santa Clara, CA) genechips covering all the mouse olfactory receptor genes, and in situ hybridization, we achieved a relatively complete expression profile of the olfactory receptor genes in the septal organ. The majority of the septal neurons express only a few receptor genes in varying patterns, with the top one in ϳ50% of the cells and the top eight together in ϳ93% of the cells. We demonstrated that a single neuron expresses only one receptor by a thorough combination of all the major septal receptor genes in double-labeling studies. These septal receptor genes do not form a single subfamily. Instead, these genes are distributed on a few major branches of the phylogenetic tree covering all the mouse olfactory receptors. Most of these genes are also concentrated in certain areas within the most ventral zone of the main olfactory epithelium, although their expression patterns do not match those in the septal organ. In contrary to the previous view of random distribution, our results indicate that certain olfactory receptors form "hot spots" in the nose.

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“…Because odor concentrations in this study were well above threshold (around 0.1-5% of saturated vapor at 1 L/min flow rate), it is not clear why odorant capture would be a limiting step for discrimination. Although relatively little is known about how sniffing parameters affect odorant capture, simulations of fluid flow suggest that higher inspiratory flow rates direct more air toward the olfactory portion of the nasal cavity (Kimbell et al 1997;Wilson and Sullivan 1999). Our technique did not measure flow rates directly, but it has been shown previously that frequency and flow rate are correlated (Walker et al 1997).…”

Section: Behavioral Correlates Of Sniffing Frequencymentioning

confidence: 94%

“…For rats the frequency of sniffing is typically in the "theta" frequency range (4 -12 Hz) during olfactory discrimination (Rajan et al 2006;Uchida and Mainen 2003;Youngentob et al 1987) or exploration (Welker 1964), but how accurately sniffing frequency can be regulated and whether olfactory performance depends on the exact sniffing frequency is not known. Respiratory airflow and several other character-istics of sniffing covary with its frequency (Walker et al 1997;Youngentob et al 1987), so high frequencies could enhance olfactory transduction (Hahn et al 1993;Kimbell et al 1997). Alternatively, particular sniffing frequencies within the theta (4-to 12-Hz) range may be favorable for the coordination of olfactory processing with other brain regions (Kay 2005;Kepecs et al 2006;Komisaruk 1977).…”

Section: Introductionmentioning

confidence: 99%

Rapid and Precise Control of Sniffing During Olfactory Discrimination in Rats

Kepecs

Uchida

Mainen

2007

Journal of Neurophysiology

191

207

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Kepecs A, Uchida N, Mainen ZF. Rapid and precise control of sniffing during olfactory discrimination in rats. J Neurophysiol 98: 205-213, 2007. First published April 25, 2007 doi:10.1152/jn.00071.2007. Olfactory perception relies on an active sampling process, sniffing, to rapidly deliver odorants from the environment to the olfactory receptors. The respiration cycle strongly patterns the flow of information into the olfactory systems, but the behavioral significance of particular sniffing patterns is not well understood. Here, we monitored the frequency and timing of nasal respiration in rats performing an odor-mixture-discrimination task that allowed us to test subjects near psychophysical limits and to quantify the precise timing of their behavior. We found that respiration frequencies varied widely from 2 to 12 Hz, but odor discrimination was dependent on 6-to 9-Hz sniffing: rats almost always entered and maintained this frequency band during odor sampling and their accuracy on difficult discrimination dropped when they did not. Moreover, the switch from baseline respiration to sniffing occurred not in response to odor delivery but in anticipation of odor sampling and was executed rapidly, almost always within a single cycle. Interestingly, rats also switched from respiration to rapid sniffing in anticipation of reward delivery, but in a distinct frequency band, 9 -12 Hz. These results demonstrate the speed and precision of control over respiration and its significance for olfactory behavioral performance.

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Computer Simulation of Inspiratory Airflow in All Regions of the F344 Rat Nasal Passages

Cited by 183 publications

References 31 publications

Localization of eNOS in the Olfactory Epithelium of the Rat

Localization of eNOS in the Olfactory Epithelium of the Rat

Molecular Organization of the Olfactory Septal Organ

Rapid and Precise Control of Sniffing During Olfactory Discrimination in Rats

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