Vomeronasal organ mammals

Kratzing J.E. (1982). The anatomy of the rostral nasal cavity and vomeronasal organ in Tarsipes rostratus (Marsupialia Tarsipedidae). Aust Mammal 5, 211-219. 

Tirindelli R., Mucignat-Caretta C. and Ryba J. (1998). Molecular aspects of pheromonal communication via the vomeronasal organ of mammals. Trends Neurosci 21, 482-486. 

Wysocki C.J., Beauchamp G.K., Reidinger R.F. and Wellington J.L. (1985). Access of large and non-volatile molecules to the vomeronasal organ of mammals during social and feeding behaviors. J Chem Ecol 11, 1147-1159. 

These cues are important in rearing, territorial, courtship and, in particular, sexual behaviors. The vomeronasal organ (VNO) is separate from the main epithelium in mammals, comprising a thin epithelial tissue within a bony capsule in the lateral wall of the nasal cavity. It is probably vestigial in humans. The VNO epithelium contains at least two populations of microvillar chemosensory neurons one is in the more apical aspects of the epithelium, while the other lies in the more basal region. These two populations of vomeronasal neurons (VNs) are defined by the differential expression of several genes. For example, the apical VNs express the G-protein subunit Ga, while the basal neurons express Ga0. Apical and basal VNs also... 

As with many macrosmatic mammals, rodents have two separate chemosensory systems, the main olfactory system (MOS) and accessory olfactory system (AOS), which respond to social odors. Importantly, these sensory systems differ not only in their peripheral morphology and central projections, but also in the types of chemosignals that they process (Meredith 1991). Sensory neurons of the MOS, which are located in the main olfactory epithelium and project to the main olfactory bulbs, process volatile chemicals and can detect odors at a distance. In contrast, sensory neurons of the AOS, which are located in the vomeronasal organs (VNO) and project to the accessory olfactory bulbs, primarily process large, non-volatile chemicals and require contact for stimulation (Meredith 1991). 

Apart from taste, vertebrates have five different chemoreceptor systems for airborne chemosignals the main olfactory system, the vomeronasal organ (VNO), the trigeminal nerve, the septal organ of Masera, and the nervus termi-nalis. They each will be discussed in turn. All five are fully functional in most mammals (Fig. 5.1). 

Table 8.2 The role of the vomeronasal organ in priming in Mammals...

Most mammals have a second olfactory apparatus, the vomeronasal organ (VNO) or "sexual nose," which is located on the lower surface of the nasal cavity. It is a fluid-filled cavity containing chemosensory receptors through which nasal fluid is literally pumped, when the animal seeks to maximize the sensitivity of detection.908 915 The VNO is especially... 

While pheromones are known to mediate a variety of behaviours in other mammals, the human vomeronasal organ (VNO), which conveys information about pheromone eoncentration to the brain, was believed to be absent or atrophied in adults. It was also believed to lack any... 

Herrada G, Dulac C (1997) A novel family of putative pheromone receptors in mammals with a topographically organized and sexually dimorphic distribution. Cell 90 763-773 Huh GS, Boulanger LM, Du H, Riquelme PA, Brotz TM, Shatz CJ (2000) Functional requirement for class I MHC in CNS development and plasticity. Science 290 2155-2159 Inamura K, Kashiwayanagi M, Kurihara K (1999) Regionalization of Fos immunostaining in rat accessory olfactory bulb when the vomeronasal organ was exposed to urine. Eur J Neurosci 11 2254-2260... 

The vapor pressure criterion pertains especially to animals that possess sensory apparatus that humans lack. Many mammals have a morphologically distinct chemo-sensory organ called the vomeronasal organ (VNO) (Meredith, 1998), which is vestigial in human beings. The VNO appears to respond to nonvolatile chemical stimuli that arrive as airborne particles. The VNO may also have the capacity to detect volatile stimuli, and the remaining guidelines help differentiate its inputs from olfaction. 

Figure 2. The Harderian gland, nasolacrimal duct, and vomeronasal organ of (A) squamates, (B) caecitians, (C) anurans, and (D) mammals. C Med cavum medium of nasal cavity/fC Harderian gland, NLD nasolacrimal duct, T tentacle, n O vomeronasal organ. After Hillenius 2000 (A, B, D) and Hillenius et at. 2001 (C).

The two components of the VN system examined in the present study are the vomeronasal organ and the accessory olfactory bulb. The VNO is a paired, chemoreceptive structure present at the base of the nasal septum in most terrestrial mammals, amphibians and reptiles. The VNO s bipolar receptor neurons detect pheromonal signals (Halpem, 1987 Farbman, 1992). 

The external sensory organs are drastically reduced, the eyes reduced to subcutaneous lenses (Sweet, 1906) while the ears are represented externally only by small holes surrounded by dense hair. In contrast the olfactory bulbs and tubercula olfactoria are enormous (Johnson Walton, 1989). Furthermore the vomeronasal organ is well developed and displays extensive associated glandular development and vascularization (Sweet, 1904). Generally N. typhlops shows an extremely simple cerebellar cortex for a mammal (Burkitt, 1938). 

Are there human pheromones Fiftyyears ago, Peter Karlson (1918-2001) from the Max-Planck-Institute for Biochemistry in Munich and Martin Liischer (1917-1979) from the University of Bern introduced this concept for substances, which are sent out by an animal in order to achieve a change in behaviour or a physiological response in another animal of the same species. [5] Mammals pick up the pheromones in special receptors in the vomeronasal organ (VNO, Vomer - an unpaired facial bone in the skuU) [6] located in the nasal cavity. [7] The information is transmitted to the hypothalamus, which influences the endocrine system. Until a few years ago, it was believed that in adult men the vomeronasal organ is atrophied. Then an intact VNO was discovered in the proximity of the nasal cavity s partition wall (Septum nasi). [8, 9]... 

The subject of the present work is the highly developed chemosensory system of the elephant this system includes both the primary olfactory and the vomeronasal organ (VNO) systems. In such an intelligent mammal, separation of the chemosensory responses from auditory, tactile, and visual responses is difficult. A chemosensory response by the elephant depends on reception of a chemical signal, but its expression may be modified by an intricate combination of other cues, visual, tactile, and auditory, and by the physiological state and experiences of the animal. 

Flehmen (or lipcurl) is a response of male mammals primarily to female urine. It is seen primarily during the reproductive season and might function as a means of transport of chemicals to the vomeronasal organ (286). To elucidate the components of female urine which release the flehmen. Crump et al. (277) fractionated the urine of black-tailed deer Odocoileus hemionus columbianus and observed that behavioral responses disappeared completely before fractionation had reached the level of a single component. Similar results were found with beaver (287). 

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